Automatically pick from drop down list based on criteria

I'm an engineering student and i'm trying to make excel automatically design my sections to have the most optimal design.

As you can see I have a drop down list of sections which is placed in order from lightest section on the bottom to the heaviest section on the top of the list.
I want Excel to change the sections starting from the bottom of the list to the top until all the criteria on the right say "OK". Then when all the criteria say "OK" it has to stop on that section.
It's also very important that it does this starting from the top floor (level 5) to the level one, first the braces, then the beams, then the columns. The order is important as well as the forces on the columns depend on the braces and beams I've placed.

What I do now is I open the drop down list, hold alt+arrow keys and press enter, one by one ... until the section works. I really want to find a way for it to do it on its own cuz it's pretty long.

I've tried using the what if tool, but I don't think it works in this case so I think I need to write a macro. I have absolutely no idea how to do that. Never used macros before.

I use Excel 2007.

I've attached a picture. Thank you guys for your help!

Excel help.png