The GE Cell Fusion
products are possibly overkill for your needs since they will accommodate two cell phones and an optional land line service. I have been using their Cell Fusion Cell Manager DECT 6.0
system for several years. Their Cell Fusion Gateway
box might be more what you are looking for since it uses your in-house telco wiring and standard telephones instead of wireless DECT phones.
I use it for two cell phones and a Vonage VoIP connection and the only "problem" I have had with it was that its automatic bluetooth association did not work reliably with the Samsung cell phones that I use. In theory you can associate your cell phones with the Cell Fusion controller, and the cell phones will automatically connect anytime they are within range, but I have found that I usually needed to manually remake the bluetooth connection anytime I come home (which I prefer to do anyway, so I have simply disabled the auto connect feature for consistency).
The only other "problem" I had was getting used to the idea of answering my cell phone with the DECT handset instead of the cell phone. The confusion factor was that (at least with the Samsung cell phones I use) both the cell phone and the DECT phones ring at the same time, but the cell phones can't actually be used to answer a call when their bluetooth radios are connected to the Cell Fusioncontroller. Possibly other cell phone models might either disable ringing, or also allow local answering to minimize that confusion factor.--
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