Creating a special kinematic model

Winos

Hello,
I have a question by creating a kinematic model. I would like to create a trackmotion (coordinated with the robot). The special thing is, that the carriage carrys a second carriage which is not coordinated with the robot. The carriege of the Y-stroke is driven by a pneumatic cylinder on two fixed positions.
So I don't have clou how to set up this kinematic model.

Have anyone experiences with requirements like this?