Combining Efforts - rules?

[True Neutral]

Are there any rules regarding combining efforts on an action? I'm thinking of the type where two or more namegivers can work together towards a common goal, like researching item history or performing together on stage. One similar circumstance is when a teacher helps a magic user learn a spell that the teacher already knows (Player Guide, p.251) - in that case you get to add the teacher's entire rank to your roll. In the case where it is an effort on everyone's part though are there any methods you've used?

Adding together successes? Perhaps with slightly higher difficulties to reflect the effort of working together?

Taking the best roll and adding only the extra successes of everyone else?

[Slimcreeper]

I have been thinking about something like having a lead on the test who can choose assistants. They make a test against their own step number (i.e., an average result). If they succeed, they add +2 to the lead's result. If they Rule of One, there is a -2 penalty. GM determines a reasonable number of assistants. Pushing open a door, maybe only one can help. Researching gooseberries, any number of people in a library.

[PiXeL01]

I think some traps have a team effort mechanism where you simply add the steps of the entire team together and then get one roll.
It could be simplified into in case of Talents the ranks of the team are added together and you get one roll with the team leader adding his stat step.
That becomes funky with defaultable skills however.

[Telarus]

My 1-minute turn mass combat rules are currently based around the idea that a leader can add their Unit Size to their Attack Result (Missile/Melee/Unarmed step, just not rolled), and that each success scored activates a squad in the unit for damage. Squads add their "Squad Step" (Challenge Rating, +2 for every squad member after the first) to one Damage (Effect) test per turn.

Squads in individual combat rounds add their Size (2-5) to their Standard Action(s), and their Squad Step (as above) to one Damage (Effect) test per turn.

I hope I can share more of the Airship and Riverboat rules soon.