XF 1.5 stop users from posting URLs in a group

I don't see a way to stop users from posting links when they are part of a group. I added a group called 'AGD Member Ltd' and restricted those permissions with a lot of 'deny'. But there isn't a way to stop the user from posting links :(

I searched and saw 2 threads referencing add-ins, but one is no longer here... and the other has 1 star saying it doesn't work.

What can be done? This is a terrible 'miss' in the functionality, IMO. It's pretty easy for a spammer to post links and there is no way to set up a user such that they cannot post links until they promote into the right user group (from what I can tell).

Any advice or [hopefully] I am missing something?