opposing sled movement constraints

[PaoloR1]

Hi.
someone knows how to put constraints to make sure that example, two skates on a track are attached, but if I move a skate in one direction, the other moves on the opposite side, moving away?

thanks and good work to all.

Palo

 

[eugenesis]

manage parameters-win values in the panel (fx) linking them to each other and inverting the sign (+ or -)..