How to exclude second and fourth Saturdays in TAT column

Question

I am calculating TAT using NETWORKDAYS, but it excludes all Saturdays and Sundays. I need it to exclude only the 2nd and 4th Saturdays, along with all Sundays. How can I achieve this?

Here is the existing formula

=IFERROR(ABS(NETWORKDAYS([Site Visit Start Date]@row, [Drawings Sent to Designer Date]@row)), "")

Paul Newcome · Accepted Answer

You would set your working days to include every Saturday then have a second sheet somewhere containing a date column with all of the Saturdays to skip. You would reference this column in the reference sheet as the [holidays] portion of the NETWORKDAYS function.