This is a topic that the book doesn't really talk about, or if it does i missed it. During one of our fights, our siccomancer (air magic) used a spell to launch our were-tank (he's got a ring that summons armor, we used the werewolf template for him) across a map and he then punched a stone demon, one hitting him. I love letting my players beign creative, but the question came up that they should get a bonus to the attack for this. How should I handle granting bonuses when they work together to combine attacks?
I remember seeing that in the book and I have some in mind myself, it's a Maneuver. here's your answer and enjoy!!! :)
Teamwork page 208 "You can also use maneuvers (even outside of conflict) to coordinate on an action with several people. To do this, one main character is chosen to make the final action roll (usually the one with the highest skill), and everyone else makes a maneuver roll with a skill that could potentially be used to assist. The difficulty for the assisting roll should be one or two less than the difficulty for the main action. Each helper who makes the maneuver roll places an aspect on the main character, something like Assistance from X. The main character can then tag all of those aspects when he actually makes his action roll (so he can take advantage of the help without spending a bucket load of fate points). Enough people coordinating can often lead to herculean success—many hands, after all, make light work."