Is the partnership the group? Or is it a group and a separate partnership?
I'm going to answer based on what I think you are asking.
Your husband works for a group and billing is done under the group NPI & EIN, and payments go to the group. In addition to that your husband does some private work and wants to bill for that separately with payments going directly to him. Yes it can be done but you need to contact each insurance carrier to have him set up under his SSN (or tax ID if he has one for himself) & individual NPI as well as attached to the group. For Medicare he would have to do the EFT form for his individual information as well to deposit the money into a bank account in his name.
I hope that answers your question.