One possibility that will mostly solve this problem is a Bag of Holding III and a set of Ring Gates. What you do is you have all of your party members but one hop into the bag of holding, and then have the remaining one drop the bag through one end of the ring gate. Have the 'home team' either send a signal or return to the bag at a predetermined time, and the 'away team' can pull the bag back through.
You can pass 100 lbs of material through the ring gate per day, and the Bag III only weighs 35 lbs, so you can do this once per day. You're limited to 100 miles, and you have to leave at least one person on the far end, so this isn't totally ideal, but it's reasonable. This would cost 47400 gp.