The Peace Ambassador Center will presumably be a recruiting center or meeting location for the Peace Ambassador Program. The Program appears to be operating out of the Visitor Embassies, with a higher command station on the Motherships. Tyler frequently went there because he was an Peace Ambassador. It appears that the 29 potential breeding candidates for Lisa were all recruited by their respective Peace Ambassador Centers, where they worked as Visitor Peace Ambassadors. So the Peace Ambassador Centers could be a cover to keep track of the 29, as well as to have them within easy reach.