Thanks for reading through my typos :-)
We've done apartment buildings where the Viking Apartment entry system allows 911 and direct tenant access. In essence, you would be doing the same thing, only you also provde intercom service to tenants without local landlines.
I'm not going to get into the "leaky loop" question where that tenant is also able to make short outbound calls to toll free numbers and it seems that a "condo association" ought to be able to spring the sharing of a line for such purposes as they would for any apartment entry system.
You're looking for 3 items: a Mitel SX-200 Analog cabinet, a Mitel Smart1 PAV dialer, because the generic 216/217 software has no useful toll restriction, and a Viking Apartment entry system if you don't have one already. This limits your lobby dialing to tenants numbers and 911.
The Mitel PBX can come from a company called Genesis telecom at somewhere near $1800, the Smart1 from eBay or me for about $50, and the Apt Entry sytem from a Viking Distributor for about $700. Mark the lot up 1.5 and add a few hundred bucks for installation and materials and you get about $4K :-)
Just for fun, I found my last Genesis quote for a 4x80 Mitel SX-200 w/o console. You're probably looking at something slightly less with a single shelf, 6 less station cards, and a console. Freight is still about a couple of hundred.