Help with solver - reverse combinatorial problem / transportation optimization scenario

Hi all,
I am user of this forum since almost an year now... and during all this time I found a marvelous resource of information in this forum. I felt like I have discovered a treasure of some sort

I really appreciate everyone's work here. I have never felt the need to open a new thread as I always found my answers among other threads.

I am a medium-skilled excel user, I have also managed to develop some skills with VBA... but never used the Solver add-in.

I am not proficient when it comes to Solver (I just recently discovered this great tool inside excel and I need some help understanding how it can be made useful for daily use).

This time I have stumbled upon a genuine problem for the solver.
I would need help in building up the scenario of my problem, setting the problem correctly (and if possible - some extra comments around that).
Please see the attached. I am not really sure I have even built my scenario correctly, given the image scenario and text.

Thank you in advance for any immediate support you guys are able to provide.

Kind Regards,
Jon