Ideally you will have the proper length and ID tubing to always have the proper carbonation while serving without excess foaming. The trick is hitting the proper resistance for the carbonation level and temperature.
However, it's often much easier to turn the pressure down during a party and then turn it back up for when it's going to sit for a while.
Do a search for BMBF. It's a handy, cheap, homemade bottle filler that works pretty well.