I think so.. sorry not so good with the understanding of everything..
We basically have our main site w/ two tenants, approx 30 non DID ex's in one, approx 6 non DID ex's in another.. I am not in my office all the time so I forward always my extension number to my cell phone number...
So if tenant 1 calls my extension, i get the main # for that tenant
And if tenant 2 calls my extension, I get the main # for that tenant
So i know what tenant the calls are coming from but not the exact extension who made the call to my extension
Setting my iphone up as an extension does fix this so when they call my iphone extension i actually see the extension calling me but it just won't work unless the app is up and running (which will not work for me!)