Instead of allowing players to insta port from pk at all times to different realms. Make them leave the pk to some other location in order to port. For example, you are an Alb group with the task in Hib. You go to Mid to cut off the Mid zerg reinforcements before they have an opportunity to port to Hib. This gaurantees that Mids are split between the zerg in Hib and their hometown in Mid.