Include customer group selection on registration form (v.1.6.0.9)

[FrankDrebin]

I have a store (v.1.6.0.9) with a 2 customer groups: normal and wholesale.

I would like to know if there is any way to select in register form if customer is a wholesale.  And in case it is a wholesaler customer, cannot log in automatically and I provide the access data.
I looking for a solution and I have not found anything for this specific problem. I would appreciate if someone can tell me if there is the possibility of doing so, either via code or through some module.

Thanks in advance.