While I reckon you have a choice of 3.....and you'll have to work out which is nearest/most appropriate.
Don't forget, you can join one group, but still 'help' the neighbouring groups.
Around you are;
West Midlands (just starting up - and the one I'm in)
Gloucestershire & Worcestershire
Herefordshire
I'm sure people from the other 2 groups will pop up here to try and get you to join