Transfering call from one pbx to freepbx

some user use pbx1 witch is a mitel and call extention on it. I would like to ring extention on my freepbx based on what extention is called on the other pbx…

I would add all the acount inside trunk, then i would need to ring extention based on what was called and not the did. so for example someone on pbx1 call extention 99 it be related to would then ring extention 99 on my freepbx.
I think I would need to do something about context of the trunk, but i’m not sure.

Can someone explain me what would be need to do.

Use ‘from-did-direct’ for the context of that trunk