The problem with multi computer setups, is you are running more than 1 team, and those teams don't really know much about the other team.
You can setup the Variable Keystrokes table for the character set, by select the Character set in the top left, in the lower left make sure the character set is selected, and in the lower right, select Variable Keystrokes at the top.
I don't believe that will solve your issue though, because that is for setting up slot 1 to slot X, and in multi computer, you have two slot 1s, two slot 2s, two slot 3s etc (depends on how many in each team). Essentially each team doesn't really know much about each other, but they can all receive commands from your current main, depending on the target used for the actions.
Probably the best way will be to setup a couple more variable keystrokes for "Target other PC slot 1" and "Target other PC slot 2" etc, and then add those to your variable keystrokes table with the appropriate Fkey, and then adjust the ISB42 - Party -> Follow Me (Target Slot) mapped key, you change the existing action to target "(Follower&local)&~self" , and the add in a second action for "Target other pc slot {SLOT}", with a target of "Follower&~local".
e.g.
For more info....
http://isboxer.com/wiki/Targetp.s., the above suggestion will only work if you are only using 2 computers... 3 computers requires different target techniques and a lot more thought.