How can I design a double mass-spring damper system in equilibrium?

[eggwomen]

Hi!
I have this project on my CAE classes in which I have to design a system like this,

which would be in equilibrium, so i guess that the masses should move with the constant amplitude. I have no idea how to calculate the k parameter, I tried to do this analogically to mass-spring damper system, but nothing good came out of it. Can anyone help? Would really aprreciate :)

 

[jack action]

http://people.clarkson.edu/~estradjm/FinalProjectDNS.pdf should help you. Look for "half car model" or "quarter car model" for more examples.