Sponsor Question

Hi all,
I will ask the potential employer next week but I was wondering if someone here would know the answer.

I am currently on a Tier 2 Visa and have been offered an interview for a new role.

I applied for the position on Company A's website. The job is with an organsation described as a 'joint venture between Company A and B'. Both Company A and Company B are approved sponsors. Therefore would this so called joint venture be covered by either of the sponsor licences of Companies A or B?

I appreciate that this is probably a unique question that only the employer could answer, but if anyone has any insight that would be appreciated.