Security Clearance as Sole Proprietor

Good Morning,I have a general questions about DoD security clearances and doing work as a sole proprietor.If one were to possess a TS security clearance already with a current employer, can be leveraged when bidding on potential work as a sole proprietor?When going from one company to another, I believe the FSOs of both companies facilitate the clearance transfer, which is farily straight-forward as long as the agency accepts the transfer. However, how would this take place if someone was going into a sole proprietorship?My understanding is that larger companies have a facility clearance with a facility security officer. Since a sole propriotor would not have access to those resources, how would this process work? Would the government client or prime contractor serve as the FSO? Also, is it possible to be working on multiple classified contracts simultaneously?Thanks