B team

I posted this in the Editors hideaway but not got any response so I thought I would open it up to the wider public in the hope someone would be more likely to come across it.

My problem is about the B teams in spain. I want to take over Sant Andreu in B3, but they don't currently have a B team. Would they automatically get one if I got them promoted to adelante or BBVA?

If not, is implementing one in the Editor easy enough? I would want them to participate in a lower league with the potential to get into the active leagues. I don't want to attempt to edit one in yet coz I think I would mess it up and not implement it correctly. I would miss something I think that would probably be important!