VBA - Advanced Filter / Find Row Items To Remove Based On Multiple Criteria

I'm working with many rows of data (500,000+) and many columns. To simplify my question, I'm going to provide a simple example using made up numbers and only the columns I'm concerned with.

BillT Doc.ItemQty
F11231012.00
F2123205.00
S1123105.00
RE321202.00
F2321108.00
F2321201.00
RE321203.00
RE999808.00
F27771001.00
RE7771001.00

I am trying to remove the docs that have two Bill types that cancel each other out, where the qtys match and highlight the rows where the qtys don't match. The macro needs to have the positive and negative bill types programatically entered, where for example F1 and F2 are positive and S1 and RE are negative. Keep in mind the data may not necessarily be in order as it is above.

So for example with data above, the rows for doc 777 would be removed completely because the item numbers are the same, the qty is the same, and the bill types oppose each other. Doc 123 and Item 10 lines should be highlighted since their bill types are opposed bu their qtys don't match.

I hope this makes sense. I tired to achieve this using multiple loops and arrays, but ran out of memory when working with the entire set of data. I'm assuming their must be a better way to do this, I'm hoping some of the intelligent individuals here will be able to point in the right direction.