Maybe have soc representative(s) in each society. This would be the person to contact for questions related to their area. Each soc rep would have all other soc reps in their FL. So if a crafter needs a steady flow of alternative ingot to make welding wire, he'd get in touch with his soc rep who would then get in touch with the soc rep of the space trader soc, and that rep would ask his soc members for a volunteer to arrange delivery of the alternative ingot. Then the soc reps would get the two parties in touch with each other. We'd probably also want to have several reps in each soc since one isn't online all the time.