The other Atlassian server products we have (Jira, Confluence, BitBucket) use a "*-user" group to define which users in a directory have access to that service. We have a couple directories defined, managed by Crowd, that are shared by these products.
However, HipChat doesn't implement a "*-user" group. If we use the same directories as above, we would go over HipChat license. The suggestion now is to create a new directory that has just the HipChat users (https://confluence.atlassian.com/hipchatkb/hipchat-server-synchronizes-all-users-from-crowd-directory-765399811.html), but we're now running into the issue where the double counted users are getting us very close to the Crowd license limit.
HipChat server should support *-user group so that it integrates better with Crowd and how it and other products manages user access, instead of requiring custom filtered directories and duplicated users.