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

Neither the FAR nor DFARS addresses use of Intergovernmental Personnel.  Any member of a source selection team is required to sign various documents to include a Non-Disclosure Agreement.  We offer that an IPA position cannot serve as the Source Selection Authority, nor should the person hold a voting or decision-making position.  We see no reason an IPA person cannot serve as part of the evaluation team with the abilities we grant support contractors, i.e., to serve as subject matter experts or advisors.

If using IPAs, you will want to notify industry in your solicitation of your intent to do so.  Some company may perceive this as some sort of conflict of interest or disadvantage to them.  You put it in your solicitation, so the question gets raised and resolved early rather than in the middle of the selection process.  Check for any NGA implementing directives or guidance to see if your agency has a more specific reading.