It appears that you want to build a simulator like Hysys that solves blocks backwards and forwards instead of just forwards like most sequential modular flowsheet programs. Can it be done? I always assume it can be done in Mathcad, until proven otherwise. Even then, I assume the objective can still be met, but maybe the implementation will be different than initially desired.
I think you will end up with a bunch of functions that you collect into one solve block and solve them simultaneously. Seems possible.
I have corrected your test 2 file. See the comments in the file.