New Post: User Groups

Is it possible to create user groups in bugnet. I would like to make user groups and send notification to that goup alone, if I am selecting a particular category.

1) For a project two groups are there - Designers & Developers
2) Categories also two - UI & Web
3) When I am entering a new issue under category 'UI', I should be able to send notification to Designers only.

Is it possible? If possible, how to do that?

Regards
Ceema