That definitely would be the ideal answer, but the way these actual workbooks (not my example book) are set up make this solution quite complicated. For example, how does that work if the worksheet that the values are being entered in are from another workbook? Also, based on the primary value being entered in, the value is referenced in 1-5 different workbooks which means that the code will need to look at all dependent workbooks every time it runs.

From my novice perspective, it seems much more straightforward to have a code that simply "click + enters" the cell in column B on Workbook Open if there are values in columns D, E, or F.