xxovermetalxx,
Do you currently have a Bluetooth module or a DECT Module on the phone?
If you have a Bluetooth module it can support up to 6 devices and one of those could be an external speaker phone like the Logitech® P710e Mobile Speakerphone.
If you already have a DECT Module then this is not an option and going with the UC360 would be your best bet unless you wanted to go with a traditional analog speakerphone. If you go with the UC360 and your software version is at least 5.0 then you can setup a Dynamic Extension between the two phones and then use the handoff feature to send over to the speakerphone or they could do a reverse transfer from the UC360 from any other phone on the system. I would not however try to setup the conference call on the UC360 though, but use the conference assistant or the 5360 to start the conference and then move it over to the UC360.
Thanks,
TE