I want to be able to define multiple parties, with a simple scene that allows you to switch between parties.
For example, you are in a dungeon that requires you to split up your party into two teams.
Each team will go through a series of puzzles in order to proceed, and in the end both teams have to push a button before meeting up at the end, where the teams will be merged into one again.
The script should be written so that any code that depends on the existing $game_party does not need to be touched (that is, even if we have two teams, the "current" team will be stored in $game_party so that things like exp share is only given to the current party).
The party switch scene can be simple: just use the file save scene which will display all of the parties.
I saw Fomar's multiple inventory script and thought it was pretty interesting.http://cobbtocs.co.uk/wp/?p=135
The multiple party system should be set up so that the developer can choose whether parties will have separate inventories or not.
A scene for swapping items between parties should be made available for those that wish to enforce separate inventories.
Now a problem that might occur is when two parties merge, their inventories get merged. Behavior for this is undefined and so I would just say merge the inventories and let others deal with it as appropriate.