Help with grouping

im wondering if anyone can shed a bit of light on my troubles

I have 3 databases users (people who sign up) database users (people who sign up can add records) groups (I’m wanting users to be able to add database users to groups)

however I’ve made it so users can only see database users they have added. The same for groups.

i can’t work out how to allow them to add and remove people from the group from the forms below. what would i need to add

here’s the visual funnel