Lanefan
Victoria Rules
Whatever Party A ignores, Party B - which may or may not be run by the same players - cleans up.but then we are back to choices not mattering, whatever I ignore, someone else cleans up
Sometimes there's simply more needs doing all at once than a single party can handle, e.g. of six characters in a party, four have just picked up unrelated-to-each-other quests that have to be seen to right now; meaning you're staring down the barrel of running four parties* rather than just one.
* - not necessarily all at once, it's easier to run one for an adventure then put it on hold and jump to another - I do this all the time.