Tree style cell organization

It may be a bit difficult to explain what I'm trying here, but bear with me:

I am making a spreadsheet that contains sales information on different products. (for someone that is familiar, it's for the video game EVE online)
What I want to do is separate the cells and their formulas based on their parent item without having to make a sheet for each item. Trees come to mind, though I haven't used them so I'm not sure they're what I'm looking for.

For example, I have 50 orders for a particular item, but the price changes before the order is completed so I need to create another row for the same item, just with a new quantity and price. The catch is, there is a broker's fee which I only need to factor in on the original 50 item order, so the formulas I have for profitability can't just be dragged down.

What I want is to have a parent item representing the first order, followed by suborders that don't factor in the broker's fee. Preferably I want this in a way that allows me to drag the formulas down and expand each item with their own, separate formulas dependent on the parent item.

I know it's a little hard to follow, but I hope someone has an idea of what I mean and I hope that it is possible. I could always just put each item in its own sheet, but I expect to be processing a lot of items and it would be simpler to keep it on one.

Thank you, I've posted it here with comments. It's mostly an organizational thing, but I want the function to remain with collapsible parent items.

That certainly solves the conditional issue, thank you!

What is this the range: "$A$9:A11" referring to? I'm stilling learning excel, so every little tip helps. Honestly it functions about as well as I would like it to, being able to collapse the original order and following rows would just be a nice bonus :P