BeoLink "Passive" is the same as a ML/MCL Converter + "Eye" (IR transceiver) + 5m cable.
If connected to Powerlink (wo IR tranceiver) it works like as a MCL2P Power-Amp
If connected to MasterLink (wo IR tranceiver) it works like a ML/MCL ConverterMost versatile solution would be:
"BSys 2500" >> DataLink-Cable 7 pin >> "BeoLink-Converter" >> ML-Cable >>
"BeoLink Passive + New Eye" >> Passive Speakers (conected to BeoLink Passive)
(old xtra kit/old IR not any longer required but you'll need a BeoLink Converter 1611 + ML + DL Cables)
Advantage: completely independant on/off as well as volume/sound settings for both rooms possible!
you're solution will work. I would do/propose the same.