This is something i´ve been thinking about many times myself.
The most common way is propably the way you described...however i myself tend to do it most often, in the way that i, if acting as MA, attack other of the ranged mobs, regardless what the tank or anyone else does.
This might not be the best way to do it (i don´t know, never been critisiced about it), but at least it keeps one of the ranged ones out of the healer.
lately i´ve been in fellowships inlcuding LM, most often our own Worfdar

And in situations where there are 2 ranged and 2 melee mobs for example, i´ve noticed that Worf ALWAYS stuns the other ranged mob, without asking or advicing. I´m in the opinnion that this has been the most succesful way to do it aswell. If having hunter in the group too he can trap other of the melee ones, and leaving only the other melee to the tank and the other ranged one to the MA and the others. These first 2 mobs are quite quickly dealt with, after that the ranged one can be stunned again or MA moves to that one and Tank to the melee one.
Wether it´s best to do in the way, that MA chooses the ranged one and Tank the melee one at the first place, is a matter of opinnion? Just that ranged ones tend to do less damage on melee than the actual melee mobs, thus making it "easier" for the MA to handle..
Opinnions on picking ranged/melee ones? Vany? Thopor?
I think crowd control is very undervalued matter in fellowshipping, you can even see it in the way that LM´s are quite often overlooked when people are looking for men for their fellowships.
I´ve been doing enough, though not too much

, fellowshipping to notice that CC can be very essential part of smooth and fast fellowships and can sometimes just settle the entire situation.
I must stress out that i´m no expert in CC´ing as us champions have no CC skills what so ever. oh, sorry we do have that one AOE skill with that ridiculous horn, that stuns the mobs for few seconds and turns all the aggro on ourselves
I really really really hope that with the next patch, there would be some CC skills coming to our way too! or at least some useful skills, as i really do feel that us champs are starting to be the least efficient and useful class in the game.
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Burn the women, rape the houses!