Is this possible

User login to remote system from local device

I have two FreePBX systems, different physical locations, now connected by fiber.
My question is this: When using device and user mode, is it possible to have a user temporarily move to a phone that is connected to system A for its config server, and is logged in to system A as a device, yet have them login to their extension on system B from said device?

If so, when in device and user mode, if user dials an emergency number (911 for example) does it always carry the CID of the device and go out the specified emergency trunk of system A?

The phones are Aastra 6739i and the FreePBX distro is 2.11. I can trunk via either sip or iax if one is needed but seems to me that would not matter. Also, devices and users have different extensions

Good afternoon, jamiebah.

It would be a big help if in the future you would please put something in the Subject: line that more clearly indicates your question. A lot of people (including me, usually) don’t read messages unless the Subject clearly indicates it is a message of interest or something we can help with. There are too many messages in this forum to read all messages that have generic, uninformative Subjects like “Is this possilble” (is WHAT possible?).