Creating a List from Multiple Columns with Exclusion

I am creating a work schedule with many people that have different qualifications and each person fills one role per day. The worksheet needs to identify if the staffing level for the day meets the minimum number of qualified people. For example:

11/24/2017.

John.
Bob.
Jack Joe

Job 1 John Bob Joe

Job 2 Jack Joe John

Job 3 Bob

The function has to be able to determine that a) Bob must be the person to fill in for Job 3 as he is the only one present that day and b) Bob is now removed from performing any other job that day and must be excluded from the other jobs.

Thanks in advance!