How to make a custom pop-up for a group?

I want to make a popup for a group.
Like there are different member groups like newbies, inactive etc. I want that a particular group like 'Inactive' only get a pop-up saying that "they are not active, click here to know how to be active members". I think u got my point.

Thanks

sorry, we dont have popup function..

in my opinion,the popup system will be at a discount by members .