Multi Tenant Box

Hello, I have been reading the posts all day and haven’t seen a post on this recently so I wanted to ask (if I missed something, sorry…). Has a solution for having a multi-tenant box been created yet? Meaning, can I have a box with 2 seperate companies on it. Therefore Ext 101 from company A will be different than Ext 101 from Company B. And if ext 101 from comany A called ext 102, it would only ring the Ext 102 from Company A and wont attempt to reach Company B.
If there hasn’t been a way to do this yet with FreePBX, then can anyone suggest any solution that does this? How are companies offering hosted PBX services?
FYI- I am currently using Trixbox CE.
Thanks for your help!!!

You didn’t miss anything. FreePBX isn’t really for that type of use.

The companies offering hosted are running multiple instances.

try this
http://trixbox.org/forums/trixbox-forums/open-discussion/trixbox-xen-guide