diff -ur inn-2.5.2/innd/chan.c inn-2.5.2-wipgroup/innd/chan.c
--- inn-2.5.2/innd/chan.c	2010-03-24 21:10:36.000000000 +0100
+++ inn-2.5.2-wipgroup/innd/chan.c	2011-04-10 21:52:09.000000000 +0200
@@ -200,6 +200,8 @@
     cp->In = in;
     cp->Out = out;
     cp->Tracing = Tracing;
+    cp->WIPGroup = 1;
+    cp->WIPMask = ~0L;
     HashClear(&cp->CurrentMessageIDHash);
     ARTprepare(cp);
 
diff -ur inn-2.5.2/innd/innd.h inn-2.5.2-wipgroup/innd/innd.h
--- inn-2.5.2/innd/innd.h	2010-03-24 21:10:36.000000000 +0100
+++ inn-2.5.2-wipgroup/innd/innd.h	2011-04-10 21:49:36.000000000 +0200
@@ -395,6 +395,8 @@
   HASH		       CurrentMessageIDHash;
   struct _WIP	    *  PrecommitWIP[PRECOMMITCACHESIZE];
   int		       PrecommitiCachenext;
+  long		       WIPGroup;
+  long		       WIPMask;
   int		       XBatchSize;
   int		       LargeArtSize;
   int		       LargeCmdSize;
@@ -564,6 +566,7 @@
   time_t	Timestamp;	/* Time we last looked at this MessageID */
   CHANNEL	*Chan;		/* Channel that this message is associated
 				   with */
+  long		WIPGroup;
   struct _WIP	*Next;		/* Next item in this bucket */
 } WIP;
 
diff -ur inn-2.5.2/innd/rc.c inn-2.5.2-wipgroup/innd/rc.c
--- inn-2.5.2/innd/rc.c	2010-03-24 21:10:36.000000000 +0100
+++ inn-2.5.2-wipgroup/innd/rc.c	2011-04-10 21:54:29.000000000 +0200
@@ -47,6 +47,8 @@
     char	*Comment;	/* Commentary [max size = MAXBUFF] */
     int		HoldTime;	/* Hold time before disconnect over MaxCnx */
     int		Keysetbit;	/* Bit to check duplicated key */
+    long	WIPGroup;
+    long	WIPMask;
 } REMOTEHOST;
 
 typedef struct _REMOTEHOST_DATA {
@@ -85,11 +87,13 @@
 #define NORESENDID	"noresendid:"
 #define HOLD_TIME	"hold-time:"
 #define NOLIST		"nolist:"
+#define WIPGROUP	"wipgroup:"
+#define WIPMASK		"wipmask:"
 
 typedef enum {K_END, K_BEGIN_PEER, K_BEGIN_GROUP, K_END_PEER, K_END_GROUP,
 	      K_STREAM, K_HOSTNAME, K_MAX_CONN, K_PASSWORD, K_IDENTD,
 	      K_EMAIL, K_PATTERNS, K_COMMENT, K_SKIP, K_IGNORE, K_NORESENDID,
-	      K_HOLD_TIME, K_NOLIST
+	      K_HOLD_TIME, K_NOLIST, K_WIPGROUP, K_WIPMASK
 	     } _Keywords;
 
 typedef enum {T_STRING, T_BOOLEAN, T_INTEGER} _Types;
@@ -582,6 +586,8 @@
             new->CanAuthenticate = true; /* Can use AUTHINFO. */
             new->MaxCnx = rp->MaxCnx;
             new->HoldTime = rp->HoldTime;
+            new->WIPGroup = rp->WIPGroup;
+            new->WIPMask = rp->WIPMask;
 	    memcpy(&new->Address, &remote, sizeof(new->Address));
 	    if (new->MaxCnx > 0 && new->HoldTime == 0) {
 		CHANcount_active(new);
@@ -841,6 +847,8 @@
     rp->NoResendId = false;
     rp->Nolist = false;
     rp->HoldTime = 0;
+    rp->WIPGroup = 1;
+    rp->WIPMask = ~0L;
     rp++;
     (*count)++;
 #endif	/* !defined(HAVE_UNIX_DOMAIN_SOCKETS) */
@@ -862,6 +870,8 @@
     default_params.Email = xstrdup(NOEMAIL);
     default_params.Comment = xstrdup(NOCOMMENT);
     default_params.Pattern = NULL;
+    default_params.WIPGroup = 1;
+    default_params.WIPMask = ~0L;
     peer_params.Keysetbit = 0;
 
     /* Read the file to add all the hosts. */
@@ -916,6 +926,10 @@
 	  groups[groupcount - 2].MaxCnx : default_params.MaxCnx;
 	group_params->HoldTime = groupcount > 1 ?
 	  groups[groupcount - 2].HoldTime : default_params.HoldTime;
+	group_params->WIPGroup = groupcount > 1 ?
+	  groups[groupcount - 2].WIPGroup : default_params.WIPGroup;
+	group_params->WIPMask = groupcount > 1 ?
+	  groups[groupcount - 2].WIPMask : default_params.WIPMask;
 
 	if ((word = RCreaddata (&linecount, F, &toolong)) == NULL) {
 	  syslog(L_ERROR, LEFT_BRACE, LogName, filename, linecount);
@@ -975,6 +989,10 @@
 	  group_params->MaxCnx : default_params.MaxCnx;
 	peer_params.HoldTime = groupcount > 0 ?
 	  group_params->HoldTime : default_params.HoldTime;
+	peer_params.WIPGroup = groupcount > 0 ?
+	  group_params->WIPGroup : default_params.WIPGroup;
+	peer_params.WIPMask = groupcount > 0 ?
+	  group_params->WIPMask : default_params.WIPMask;
 
 	peer_params.Keysetbit = 0;
 
@@ -1053,6 +1071,8 @@
 		    RCCommaSplit(xstrdup(peer_params.Pattern)) : NULL;
 		rp->MaxCnx = peer_params.MaxCnx;
 		rp->HoldTime = peer_params.HoldTime;
+		rp->WIPGroup = peer_params.WIPGroup;
+		rp->WIPMask = peer_params.WIPMask;
 		rp++;
 	    }
 	    freeaddrinfo(res0);
@@ -1301,6 +1321,62 @@
 	continue;
       }
 
+      /* wipgroup */
+      if (!strncmp (word, WIPGROUP, sizeof WIPGROUP)) {
+	free(word);
+	TEST_CONFIG(K_WIPGROUP, bit);
+        if (bit) {
+	  syslog(L_ERROR, DUPLICATE_KEY, LogName, filename, linecount);
+	  break;
+	}
+	if ((word = RCreaddata (&linecount, F, &toolong)) == NULL) {
+	  break;
+	}
+	RCadddata(data, &infocount, K_WIPGROUP, T_STRING, word);
+	for (p = word; (isdigit((unsigned char) *p) || (*p == '-' && p == word)) && *p != '\0'; p++);
+	if (*p != '\0') {
+	  syslog(L_ERROR, MUST_BE_INT, LogName, filename, linecount);
+	  break;
+	}
+	if (peer_params.Label != NULL)
+	  peer_params.WIPGroup = atol(word);
+	else
+	  if (groupcount > 0 && group_params->Label != NULL)
+	    group_params->WIPGroup = atol(word);
+	  else
+	    default_params.WIPGroup = atol(word);
+	SET_CONFIG(K_WIPGROUP);
+	continue;
+      }
+
+      /* wipmask */
+      if (!strncmp (word, WIPMASK, sizeof WIPMASK)) {
+	free(word);
+	TEST_CONFIG(K_WIPMASK, bit);
+        if (bit) {
+	  syslog(L_ERROR, DUPLICATE_KEY, LogName, filename, linecount);
+	  break;
+	}
+	if ((word = RCreaddata (&linecount, F, &toolong)) == NULL) {
+	  break;
+	}
+	RCadddata(data, &infocount, K_WIPMASK, T_STRING, word);
+	for (p = word; (isdigit((unsigned char) *p) || (*p == '-' && p == word)) && *p != '\0'; p++);
+	if (*p != '\0') {
+	  syslog(L_ERROR, MUST_BE_INT, LogName, filename, linecount);
+	  break;
+	}
+	if (peer_params.Label != NULL)
+	  peer_params.WIPMask = ~(atol(word));
+	else
+	  if (groupcount > 0 && group_params->Label != NULL)
+	    group_params->WIPMask = ~(atol(word));
+	  else
+	    default_params.WIPMask = ~(atol(word));
+	SET_CONFIG(K_WIPMASK);
+	continue;
+      }
+
       /* hostname */
       if (!strncmp (word, HOSTNAME, sizeof HOSTNAME)) {
 	free(word);
@@ -1596,6 +1672,18 @@
 	    RCwritelistvalue (F, RCpeerlistfile[i].value);
 	    fputc ('\n', F);
 	    break;
+	  case K_WIPGROUP:
+	    RCwritelistindent (F, inc);
+	    fprintf(F, "%s\t", WIPGROUP);
+	    RCwritelistvalue (F, RCpeerlistfile[i].value);
+	    fputc ('\n', F);
+	    break;
+	  case K_WIPMASK:
+	    RCwritelistindent (F, inc);
+	    fprintf(F, "%s\t", WIPMASK);
+	    RCwritelistvalue (F, RCpeerlistfile[i].value);
+	    fputc ('\n', F);
+	    break;
 	  case K_PASSWORD:
 	    RCwritelistindent (F, inc);
 	    fprintf(F, "%s\t", PASSWORD);
diff -ur inn-2.5.2/innd/wip.c inn-2.5.2-wipgroup/innd/wip.c
--- inn-2.5.2/innd/wip.c	2010-03-24 21:10:36.000000000 +0100
+++ inn-2.5.2-wipgroup/innd/wip.c	2011-04-10 21:46:50.000000000 +0200
@@ -41,6 +41,11 @@
     new->MessageID = hash;
     new->Timestamp = Now.tv_sec;
     new->Chan = cp;
+    if (cp != NULL) {
+	new->WIPGroup = cp->WIPGroup;
+    } else {
+	new->WIPGroup = 1;
+    }
     /* Link the new entry into the list */
     new->Next = WIPtable[bucket];
     WIPtable[bucket] = new;
@@ -117,8 +122,11 @@
 		i = WIP_ARTMAX;
 	}
  
-	if ((Now.tv_sec - wp->Timestamp) < (time_t) (i + innconf->wipcheck))
-	    return true;
+	if (((Now.tv_sec - wp->Timestamp) < (time_t) (i + innconf->wipcheck)) &&
+	    (wp->WIPGroup & cp->WIPMask)) {
+		return true;
+	}
+	wp->WIPGroup = wp->WIPGroup | cp->WIPGroup;
 	if ((Now.tv_sec - wp->Timestamp) > (time_t) (i + innconf->wipexpire)) {
 	    for (i = 0 ; i < PRECOMMITCACHESIZE ; i++) {
 		if (wp->Chan->PrecommitWIP[i] == wp) {