Transfer Joint through multiple components

I’m trying to create a pedestal for robots that can be used on Robot Positioners.

The double base export is not a problem, but when I try to do a double joint export it won’t be imported by the robot.
The pedestal will import the Positioner Joint, but won’t export it.

Is there a way to export imported joints?

As workaround you could use an abstract interface for exporting/importing the joints. Take a look to a Workpiece positioner. So connect a Robot Positioner as Workpiece positioner.