Thank you again for your help Duane.
I see now the drop menu is just for topics.
What you tell me seems to support my own observations and experience that tags may have their place but finding groups is not that place.
The system I propose seems logical, simple and effective. It's an addition to what currently exists not a replacement for anything.
Apart from, "very busy at the moment" and a modest amount of work I can't see the problem unless it's ideology over pragmatism.