Tweaking AdminCP Permissions

[kontrabass]

I have some php modification ability (limited), but I'm wondering if someone can point me to the place to start:

I have a group of co-admins who will help out with user admin'ing. So they are administrators, with only 'user administration' access. However by default this also gives them access to the Paid Subscriptions area (with complete financial log), that I'd prefer hiding.

How can I revoke admin permissions, so that they cannot see the "Paid Subscriptions" admincp group?

Thanks in advance!