@Anthrazit I did not read this latest reply of yours before posting my suggestion. But fundamentally, the mechanism I outlined there could work since the material properties you transfer are probably not that many (i.e. not large arrays).
In reading through this, I am wondering whether a modular approach could also work. The sheets that deal with material properties are probably static in the sense that, once a material is defined, its properties don't change (and if things like temperature sensitivites are relevant you can save these as expressions). So you could have a module that has a number of procs that return material-specific modules or records for use in your sheet doing the structural analysis. Handing info back to the materials section would require some thought.
A code snippet showing how you could implement this:
# here is the code making up your module named Concrete
# can be constants, functions, submodules, you name it.
# A Set proc. can be used to set certain properties
end proc; # Concrete
You load the module and access its members with
(whatever would be a member of Concrete.)
I hope this helps,