Find duplicates in other columns based on the person name

Hi Team,

I am struggling to find solution for the following problem:
1. I have one column A where I am using the names of the team members
2. I have 4 or 5 other columns that represents different activities where I am tracking different activities dates

So what I need is to find if John from Column A has no different assignments from the 4 activities columns at the same date

In other words - I want to find out that John Smith has not been allocated to the 4 different activities (4 columns) at the same day and if yes, then negotiate it with the Project managers as resource overlapping issue

I appreciate your help