Mining in wings is quite good fun. The way it works is that you each get the full number of fragments from a rock. I can't remember if you all have to fire a prospector limpet, but I think not - just one has to land a prospector on the rock, but all should have prospectors in order to speed up finding the high yield rocks. You get a 20% bonus in credits when you sell your stuff if you're in a wing.
Say you have three in a wing. One has landed a prospector on the rock to show that it's worth mining. Normally you'd get x fragments from the rock, but when in a wing, each person that fires lasers at the rock will cause x fragments to come out, so you get three times as many fragments to refine. It's up to the group who collects the fragments. You can share them or one person can collect them all. Whoever collects them needs a refiner to refine them into the units that you can sell, so if you go without a refiner, you can't get anything, though it is possible to transfer stuff from one ship to another as long as you're in a wing. That means dropping it and somebody else scoops it up or uses collector limpets to collect.
In summary, to do wing mining, all ships need prospectors and mining lasers. Any ship that wants to take the fragments needs collector limpets, a refinery and loads of cargo space. It is therefore possible for two or three ships to laser the rocks and one to collect and refine the fragments. Ideally the ship collecting should be nearest the rock and the other two slightly behind and aiming their lasers directly in front of the collecting ship. That makes collecting a lot more efficient.
That works out about the same efficiency in terms of earnings for three ships as doing it individually, except that only one ship gets all the money. If you do it individually, but in a wing, you get 20% more money than doing it on your own, plus a slight improvement because each pilot can shout out when they find a good rock to the benefit of others, who would otherwise have to spend time finding it.