What area of the PMI Code of Ethics and Professional Conduct does this question reflect to, and which process are you organizing?

This question describes the Conduct Procurements process. Make-or-buy decisions is one of the inputs of this process, and bidder conferences and proposal evaluation techniques are two of the tools and techniques of this process. Since you know the vendor, even though you haven’t seen this person recently, you should be concerned about a conflict-of-interest situation.