Project portfolio selection is a complex multi-attribute decision analysis problem with a wide range of considerations. A key issue in project portfolio selection is how to evaluate different portfolio solutions especially when some portfolios are a subset of some other portfolios. In this paper, a hybrid approach is proposed to help decision makers do tradeoffs between specific pairs of portfolio solutions. More specifically, each alternative project is assigned a comparable quantitative measure based on their performances on each criterion using value function. Then, weights of the projects are determined based on their relative measures. Next, specific pairs of portfolios that need to be compared are picked out among all these solutions. Finally, a selection procedure is carried out to compare these specific portfolios in terms of their overall values, the outcomes of which can aid decision makers in discarding some unnecessary solutions. A case is studied to demonstrate the utilization and effectiveness of the proposed approach.