Medicare Enrollment

I am helping a physician with his medicare enrollment. He is a specialist that is currently working for a group practice; he is now going to start his own group practice I did his application through PECOS. There is another physician that owns half of the new group practice; I am now going to enroll him in Medicare through PECOS, PECOS is asking If I am applying as a Sole Owner of a PA, PC, or LLC; when I click that is says this enrollment application is for an individual who has formed a professional corporation, professional association, or Limited liability company, practitioner is a sole-owner of a business that is legally separate and distinct from the owner, the only medicare services provided by the business are by the owning practitioner.

Question,

Since he will not be the only physician providing services; should I be applying as a sole owner?
I applied the first physician as a sole owner because at the time he was the only one who would be providing services.