Hi, I've been looking at flight sims too. FMS has some free down loads, you just need a cable to connect your trainer jack to your computer. Maybe there is a multi-engine sim download there.
My local hobby shop was no help in finding one, they were anxious to sell me a $199 REAL FLIGHT Simulator. The software then goes for $49.95 a pop depending what you want to learn to fly. on a very fixed income so that's a bit pricey for me. I've been looking on line but did get to use a friends Dynam 6CH sim with a USB connector. It's OKAY and has a couple of helis and multi-engine fixed wing AC. I didn't fool with them, just the helis, so I can't say what they are like. The helis were easier to fly than a real RC heli.