This came up in another thread and I thought it might be useful here.
Many of us have dreaded hearing a group say 'we split up'. How do we jump back and forth, trying to keep both groups occupied and entertained? We see it in the movies all the time. Luke and Leia at the death stat chasm, Luke and Ben's one on one with Vader, etc.
Well, the beauty with the initiativr system we have is all you have to do is, if the party splits, set up the encounters for each group simultaneously. Once the groundwork is laid, roll initiative as per normal. When that player acts, the scene shifts to that group, back and forth.
While it may be tricky at first juggling between 'scenes', when you get it down you may find that players are more drawn into the game as they wait for there next turn.
Imagine a party that has equal parts fighter pilots and soldiers. The soldiers are on board a capital ship that the pilots are attacking. The soldiers have to perhaps get to the launch bay/escape pods before the pilots destroy the ship! The pilots can't let the ship jump to hyperspace so they must attack!
As stuff happens to either group you can react and relay immediately the outcome. If the pilots destroy the shield generators, the soldiers will know exactly what happened. No need to keep track of when something should be scripted to happen.
The key to this is to prepare the encounters for each group. If you can, have two scratch pads for each group (assumes equal split, adjust for more). I find that a swivel chair and card tables help immensely, as I just turn to that setup for each group.
Now this is probably common knowledge for many, but if you dread the party splitting, this may help. Think of the movies, and each player (group) is just being separated by a screen wipe - those transitions between characters on screen.