Solo 401K and employees

[Pinaki M.]

I have recently created a Solo 401(K) for a business A. This is the only business that I have so far and it only hires contractors. Now I am thinking about starting another business B. However, for business B I might have to hire W-2 employees (for example, this business can be a restaurant, or a hair salon, etc where people work on a daily basis). If that happened, can I still continue having the Solo 401(K) account for business A? Or does having employees for business B disqualify me from having a Solo 401(K) for business A too?

If yes, is there any way to work around that? I was wondering if I had a trust created (with me as trustee) and this trust is the sole member of the LLC corresponding to business B, then if that will help to continue the 401(K) for business A. Will that work? If not, then any other ideas? Note that it's not a requirement for me that I have to be able to create Solo 401(K) for business B, but at the least, I want to continue the Solo 401(K) for business A.

Thank you.