More control about who can delegate what

I like very much this module; it could be really usefull to me, if I would have some more control about WHO can delegate WHAT -
i want that only user with a given role can delegate some other role.

For example, I could have one user with role "Super user" (not delegatable) and other roles ("forum_1_administrator", "forum_2_administrator", etc.). I should give only to the "Super users" the ability to delegate "forum_1_administrator" ...

I know I could add an access option in /admin/user/access, setting up a simple function in authority_delegation.module:

function authority_delegation_perm() {
return array('May delegate roles');
}

but then I dont know how to go on :) Any help?