Nodal SDVs as a function of other nodal SDVs

Greetings,

I was recently writing an ambitious code for a certain mechanical system when I had a bright idea. Basically I have two materials that adhere together. What I would ideally like to do is deactivate the second material after the strain in the first material reaches a certain limit. So the pseudo code would look like:

If [Strain in material 1 <= Limit]

Young's Modulus of Material 2 == 0 (Or very close to zero)

end

I was using a USDFLD subroutine to do something like this, but I realized it wasn't as easy as I thought it would be since I cant seem to access SDVs of other nodes. So my question is this:

Is it possible to access current material or state data of particular nodes (especially those belonging to another material) in a usersubroutine (for example, access nodal strains of node 321) ?

And is it possible to apply a certain value to SDVs of all the nodes of a particular section assignment in the same step to essentially deactivate it ?

Or, is it just possible to 'deactivate' the loading contribution of a certain section after a limit has reached in another section ?

Thank you for your assistance,

Ashwin