Multiple H1b Visas


I’ve a question regarding H1b visa. My employer is willing to apply my H1 visa for the year 2016. My employer to client relationship is Employer–>secondary vendor–>primary vendor–>client. I’m providing the client letter to my employer with all the chain. My primary vendor is also willing to apply H1B. can he apply one more H1B? If yes, is it okay if the client is same? ( My guess is its not okay if it is the same client). can he apply with different client or saying i’ll be his future employee? I’m not sure whether he can apply second h1b cause he is in the chain for the first h1b. Any help on this will be much appreciated. Thank you in advance.