Per federal regulation the government has to believe that at least two capable companies will bid on a set-aside contract, and the way they meet this requirement is by issuing a Sources Sought
Sources Sought: A Source Sought is a mini-solicitation from the government that gives a brief overview of the work the government needs done, and requests that companies who can do the work, and who have a set-aside respond
The rule of two: If the government receives two or more responses from companies with a given set-aside then the government can set the RFP aside for that group