How to allow moderators to change usergroups ?? (alternative to adminCP)

[socialvisionsbcn]

Without giving them acces to admin panel (making them admins), how can I give my moderators the ability to change users from group to group?

I need them to control over two promotions among usergroups for users.

Is there any mod related to that??
Wich would be the simplest way to request coding for that ??