Can multiple users participate in a bounty, so
- the points they lose sum up, and
- they vote to choose the winner?
It doesn't appear to be documented as an existing feature.
This question is to discuss whether such feature would be useful.
Sometimes a featured question is difficult and can only be resolved with a sufficient amount of coding or research effort (up to a few days). But I'm reluctant to do so, because the bounty is commonly just <=150. The point in multiple users supporting a single bounty is to motivate effort needed to resolve a challenging problem.
Possible implementation notes
During the first 2 or 3 days of a 7-day bounty, people may sum up some of their reputation to increase its value. The time limitation would be to avoid the bounty value going insanely high as the deadline is approaching.