Is it possible to assign a role which only functions when user is groupadmin?

Hi all,

I'm trying to use this great module with Organic groups, which leaves me with the following question.

Is it possible to assign a role to a groupadmin that will only function in the context of that group?

Lets say a groupadmin receives a role after creation of a groupnode of a certain type.
Then he decides he wants to become a member of another groupnode of the same type he just became groupadmin of.
Now his groupadmin role of his own group shouldn't function. Instead he should receive a member role.

Hope this makes sense.

Thanks