Joomla/gallery 2 integration problem

hello, i have a problem with perrmision in gallery2 integrated with joomla.

I created website for a local photograph group base on joomla and gallery2, everything work ok - every new user has got own gallery, where can add/edit own photo, but there is some gallery categories which should be commons and then user should has permission only for own photos, now i don't know how to configure this permission because either everyone has permission or nobody!!

for example gallery categorie looks like:

- user gallery
- Bob Smith (it is ok, only Bob has permission)
- John (it is ok, only John has permission)
- common gallery
- animals (here is problem with differenet permission for different users)
- people (here is problem with differenet permission for different users)

has anybody an idea how resolve this problem?

thanks