How to sell specific products only to business customers without the need to register

[Zaneta77]

Hi, I have a problem.

I want sell some products only for business customer but without a need of registration. For example, client want buy some product (but i decide which of product could be sell only for business customer) and he put it on the basket - here should be a button or  some place to enter NIP, 
the customer enters the number, after that the button to complete the order is activated or without entering this number, the order can not be finish. Can You help me with that? Do someone know how i can do something like that? I will be gratefull for each help.