block non-admins from commenting on read only

Issue Summary

This is a great module but i'm having trouble getting around drupal's commenting permissions. I'd like to have the option to prevent non-admin users from commenting on og posts that are read only. So if a user cannot post a read only comment type, s/he can not comment on it either.

I'm guessing this would mean on the edit page for the group content type there would need to be a select box ("Not read only", "Standard read only", "Read only with read only comments") beside each group post type, and then on the edit page for the group the same select box. Is that how it would need to be done?

Or is there an easier way to do this?