We apologize for the instability of composr.app and appreciate your patience. We are working on the statistics addon and trying to find an optimal way to store and render data. Unfortunately, we have yet to find a solution that can handle the traffic (and therefore, tens of millions of statistical records) of composr.app. We're working hard on one.
This is less important now, as Sitemap nodes can be included and these automatically check all permissions. Explicit checking for manually inserting menu nodes would be nice in some rare circumstances.
{$?,{$IS_IN_GROUP,2\,3\,4},,_never_}
That should make it so that only groups 2, 3, and 4 can view the page, because anything else is going to get a match key of _never_ which can't pass.