Hello, I would like to know if using a OSD ATM 7 + Onkyo TX-NR555

I have a Receiver Onkyo TX-NR555 connected at my home as a home theater with a second audio zone solution.
I would like to validate if it is a good idea to connect an OSD ATM7 speaker selector  with my Onkyo TX-NR 555 zone 2 speakers output in order to expand the audio solution to other 4 rooms (spaces) with an afforable price. I am using russound RSF-610 8 ohms speakers.

Thanks in advance for your comments.

looks like the OSM has compensation for impedance so you should be ok just keep in mind your amp was not designed to drive 8 speakers at once (not in home theater mode). so even with compensation it will still tax your amp more as you add more pairs of speakers.  
The OSD ATM7 is a speaker switcher and does not equipped with "Impedance Matching" feature, to be safe you can select to power one zone only or your receiver might go into protection mode.
If you want to power 4 zone at the same time, you need to install a Impedance Matching Volume Control to each zone.
Or use a Impedance Matching Protection Speaker selector like the OSD ISS4 instead of the OSD ATM7.