Yes, One is set to 297, the other 456, and the receiving pipe is set to receive at both locations. I initially tested them both by sending to the receiving pipe in the same building, just to be sure.
According to Rei's minimap, both offices are ~300m apart.
On my server, I am trying to establish a Post office by using Item Teleport pipes, unfortunately, I can't get them to function, they always read 0 connected pipes even with World Anchors sitting 2 blocks away from each pipe.
I've tried Teleport Tethers as well. Are the chunk loading blocks bugged in the current version? Or is something else occurring here?