This response is based on the information provided.  We suggest you discuss with your contracting and finance team, program manager and/or legal department as appropriate.

We have tried to contact you to get clarity on your issue with no success.  With multiple award contracts (MACs), sometimes referred to as MATOCs, each winning contractor receives its own contract (individual contract number).  All material terms and conditions, performance requirements, CLIN structure, clauses would be essentially the same.  When the government issues a request for proposals, interested contractors submit proposals and those proposals are evaluated under FAR subpart 16.5.  If you ae envisioning something else, we are unclear as to what your team is trying to achieve.  We offer that any approach not be an attempt to avoid or appear to avoid legitimate, required competition.