Updating user title automatically without necessity to rebuild it via ACP?!

[Meola]

Hi there
I've created some public user-groups and I'd like my users can see their new titles immediately after joining to a new group, now it needs admin update user titles and ranks manually.
Is there any MOD or Hack for this?!

Thanks in advance

[Marco van Herwaarden]

Users can choose their display usergroup in their UserCP after joining a public joinable usergroup.

[James Birkett]

Hmm. I never have to update my usertitles. I even have a plug-in on a postbit for rotating usertitles..