establishing multiple table relationships

FeesWaived divided by Calls made =
DIVIDE(
 SUM('Employees fee waived[Fees Waived]),
 SUM('Employees Call made"[Calls Made])
)

^^^that is the quick measure I am using I am also doing the same for credits given. I think its a relationship issue because when I try to combine data from different tables and look at a monthly view of the data all my numbers are the same.  for example , I used waived fee data from  my 'employees fee waived table' and took the date from my 'employee call made' table and created achart. In this chart each month showed 1,200,000 fees waived . That is definetly not correct. In actuality some months have way more that 1.2 million and some have way less..

Can I do a merge/join if the same employees are not included in all tables? For example some employees may have made calls but they may not have waived fees so they wouldnt be in the 'employee fees waived table'. If using a bridge is the way to go can you give me a little more detail on how to do this? I am still a novice, thanks your help!!