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Excel: How to automatically format cells in Column B with the format of identical cells (values) in Column A?

I have 2 columns (A & B) of part numbers. Column A has parts that are highlighted in multiple colors. Column B doesn’t have any highlighted parts. If any one cell in Column B contains an identical part number to one in Column A, I would like to format that cell with the same color.

Example:

In this example I manually highlighted the cells in Column B to show what I’m hoping to be able to do automatically.

I have been manually highlighting Column B, but that is very time consuming. The actual file is a couple thousand lines long. I would like to use some sort of formula so I don’t have to spend the time doing it manually.

Note: The cells in Column B that are highlighted in red are unique values and are already done when I start the process. Also, I can ignore the white cells.