I found that there is an unexpected but fast way to remove a group from every databases ACL in your Lotus Notes Domain. Just rename a group using the appropriate action in your Domino Directory and oops, as you didn't want to do that, just enter the old name of the group again. Everybody would expect AdminP to ignore this request as source and target name are the same but in fact AdminP removes the group!!!! This Problem has been reported to Lotus Support and is fixed in Lotus Domino 6.5.