NEED IMMEDIATE HELP - Auto-Hide Rows Based on Data in two columns

Hello All!

This might be difficult to explain, but please bear with me.

This document I'm working on contains 250,000 rows. This can't be changed. The document needs to automatically hide or unhide entire rows based on duplicate matches in columns B and J. So as you see in the example below, B2 and J2 are unique, compared to B3 and J3, B4 and J4 and so on. So row 2 would stay unhidden. Row 3 however, (B3 and J3) matches other cells in the B and J columns, so each row that contains subsequent matches in the B and J columns would hide, but the first row that contains these duplicates (in this case B3 and J3) stays unhidden. So in the example below, Row 2,3,8,11 and 12 (highlighted in blue) would be unhidden, either because they're unique or they're the first in a bunch of duplicates. Rows 4,5,6,7,9 and 10 would hide because their cells in columns B and J contain matches. The data on this worksheet is pulled from another ducument elsewhere, so if data in that document changes and something that was a duplicate is now unique, the entire row that contains this updated data in B and J would unhide itself automatically. I know there is a way to write a VBA for this, but I can't figure out how. I'm a newbie to VBA, so if you can figure out how to do this, it be very appreciated.

--------B---J
Row 2 100 AT
Row 3 100 AA
Row 4 100 AA
Row 5 100 AA
Row 6 100 AA
Row 7 100 AA
Row 8 100 AB
Row 9 100 AB
Row 10 100 AB
Row 11 101 BZ
Row 12 101 BG