set up a town with 1 hub and 7 nodes a few years ago, set up the schools in the town last year with 1 hub and 8 nodes.
now both schools and town buildings all share a fiber network they want to link all systems together. the town has 3 digit extension with 2 group intercoms at 50% of the phones and the schools have 4 didgit extension.dont think there is anyway i can change the 3 digits to 4 and have group intercoms with out conflicts.

can i add a voip card to the two hubs and set them as tie lines? put them in line group 2 and then they can intercom each other. i know i can with a point to point t-1 but they dont have the money and there is already a fiber between the two hubs

Thanks