If I have a figure with two pistons for example, and they are each seperate groups, can ERC be used to animate them so that one piston raises as the other one lowers?  If yes then how is it done?

The other question is can ERC be made so that the object moves a certain amount, for example, if I want the piston to raise 3 in y trans can that be done and can decimal numbers be used and if it can be done then how do I do it?

Can an object like a piston be made to move up a certain amount and to move back down a certain different amount?  For example moving up in y 5 and down 3?