@Gravité Managed IT
Yes, we have done this ourselves, however, it requires you to modify manually the scripts for this to work.
1)
You need two AAD applications for each location and then configure which users shall be synced into which 3CX.(Selected Users)
2)
You need to mod. the PowerShell scripts provided, as they only deal with a single 1:1 relation. The extension of your modification depends on many factors, do the locations also need different dial plan patterns (for example to cover US and UK per location), extension length, dial codes etc. The simplest version is to only generate a second Teams SBC and add it to the routing policy.
My advice, use the default for one location, check how it works and then mod. from there your config as you needed it. Please understand, this is a complex story, therefore 3CX'ssupport end with the default setup of the trunk.