I see what you mean, but my suggestion for that would also be to use parrallel activities. Remember to the end user, it would seem the same, they would not notice that it is different activities in your process, but you can make assign Action A to Action Party A, and Action B to Action party B - however Action A and Action B contain exactly the same client event, the same rules, the same everything, it's only the name that differs.
Hope that helps,
Gerhard
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