Filter - Return multiple "under" One Criteria

So I just found out about the Filter command for Office 365 due to another post (thanks again Fluff13!).

I was immediately able to apply that to a form I'm wanting my team to fill out and got the first line to work. i.e., when you Select from the dropdown in D3, the Model comes up and the first line of the drawings come up with the Projected Hours... but that's where the issue comes in.

Right now I have a "cascade" where the Drawings (D6) are filtering off the Model (D5), and the Model (D5) is filtering off the Assembly Description (D3). That may not be the best way to do this - so if you know a better way to do all this at once, I'm open for learning!

The overall goal for the form is: when they select an Assembly from the drop down, the rest of the form fills out with "default" data, that they can then manipulate and add to the tracker (not included in the sample spreadsheet attached). So however best to do that, I'm open for ideas.

But, right now with the "cascade", it's filling in the "first line" of the drawings when the dropdown is selected, but I need it to fill in all the drawings when the Assembly Description is filled in (either through the cascade or directly, whichever is better). Basically, I want it to pull all the drawings listed next to the model, but the hard part is telling it to "stop at the blank row" (between model types).

I've tried to explain it in the attached spreadsheet... hopefully it all makes sense.

Awesome... that was a much larger answer than I thought it was going to be... thanks for taking the extra time to figure that all out. Very much appreciated!