As to the pre-amp output, see my previous posts. No that won't work.
See, you keep adding information, and the situation changes: 8 RL speakers is going to be a somewhat different thing. I presume that your using both speaker 1 & 2 at the moment for the first 4 speakers; and that'll have to change. The MCL network uses the Speaker 2 output, so you'll need to run all 4 of your current set off of the Speaker 1 output. This shouldn't put too much strain on the BeoMaster 5500, but it (and the amp in the second room, will run a little warmer than normal, so ventilation is key here.
As an alternative, you might consider building your system on the current MasterLink network, as opposed to the old MCL network. The 5500 should support that (I'll double-check, and certainly I'll be corrected again by Peter or Keith if I'm wrong). In that case, you'd leave the 4 current speakers connected as normal on Spkr 1&2, connect a New BeoLink Converter to the Tape 2 socket on the 5500, run an ML cable to the other room, attach an ML Active kit, then use the fully wired PowerLink cable, to the amp as before. This will cost a bit more, and does nothing to lighten the load on the Amp in the link room; but on the up-side, it protects the 5500 from a high current load, and gives you a network compatible with all of the current gear.
And, yes, several of us here might be able to help you find all of the parts you need.
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