In the back of the big red book there are scenario rules, one of them is for a battle between 3 and 5 players (rules are on page 406).
Turn sequence is done more in line with the
LotR game (ie I move, you move, I shoot, you shoot).
A turn sequence is established and the first player moves, then the next etc. For magic 1 person rolls
2d6, this result gives the power and dispel in the same was as usual but everyone gets a power pool and a dispell pool. You cast in order, 1 spell at a time. The person being targeted gets the first chance to dispell then it goes to turn order.
Each player then does all of their shooting before the next.
Close combat happens as normal but with there only being 1 round of it per game phase as opposed to 1 each player phase.
I've played this with me and my
VCs in the middle, standing on top of a temple that doubled the number of models I raise each cast then dwarves on one side and ogres on the other. It was quite possibly the funnest game I have ever played