A commercially available G2 Bus Connector doesn't seem to exist, so another solution must be found.
I made a crude model in FreeCAD to test my ideas on. It's only the mating side of the modem connector so far, but the side that mounts to the PCB doesn't really matter since we don't need an exact replacement.
3D printing the connector may be a viable option. I'll create a model to see if it's even possible to meet the design rules.