Walter, inheritance and can_target work perfectly fine when there are no incorrect group branches in the tree, and when there are no conflicting addons.
You COULD use !#each,!#group,!#you,!#dont,!#want,!#targeted individually, (pound sign in front of group ignores inheritance) BUT, it really would be best if you use correct inheritance trees with no branching access, that simplifies the whole specification of multiple groups.
While a trusted and a headadmin are connected, please have the host/server owner run the debuginfo and get the file it outputs