Groups documentation for module developers

I found this page from the roadmap which said that you were working on assigning activities to groups. I hope this is the right place to comment!

It would be great if not only could you assign activities to groups, but also resources.

If you teach one course but two groups you may want to give an extra resource to one group and have an activity based on it - but not want the other group to see it.

If this isn't possible then please say why, I know that I'm not the only person asking for such a capability.