Your response should be simple:
“How many people are asking for a group about [x]?”
Nine times out of ten you will get a response along the lines of:
“No-one yet, but….”
That’s when you know you shouldn’t start a group.
If people aren’t requesting or asking for a group or community, don’t create one. Instead work the audience to create the demand for such a group.
You can save a lot of time and money this way.