Can you automatically hide rows where if Column B is blank OR contains a duplicate value from elsewhere in the column?

Question

I've managed to create a list that will autofill from other sources using formulas such as =[Book2]Sheet1!$O$18

I need a Macro/Code/Whatever which will automatically hide rows where Column B is empty OR where there are duplicate values in Column B (such as if 'Mr A' appeared twice). Just the first instance should remain unhidden.

It needs to be working constantly in the background, as it's possible the original source (Sheet1) will be updated and Column B suddenly contains data, so that line would need to un-hide on my spreadsheet.

Please see screenshot to illustrate my layout.