Calculate # of Work Days btwn date & today, do not calculate if blank or if 'Not Required"

[EWolfe]

Hello,
I am looking for a formula to calculate the number of working days between the date in column A (Date of Meeting) and today "=TODAY()". However in some cases the date of meeting will either be blank or will contain "Not Required".
I have the formula to not calculate if the cell is blank:
=IF(A2="","",NETWORKDAYS(A2,Lists!$A$1,Lists!$B$2:$B$100))

Is is possible to add an additional logical test so that if the cell is either blank or contains "Not Required" then the formula will not calculate?

Thank you.