How do I exclude or include a calculated box based on its value as the Total Box at the top?

Hi -

I am building a SSRS report and I have 3 boxes which may or may not have value based on my calculations for those boxes. I have a total box on top which I want to Include value from:-

IIF(Box 1) = 0, EXCLUDE,IIF(Box2) = 0, Exclude, IIF(Box 3) = 0, EXCLUDE, SUM(Box1) + Sum(Box2) + Sum(Box3)/100)

I want this to be dynamic and do not want to hard code the values for these boxes, If 1 of them is 0 then only include 2 of them, if 2 of them are 0 then only inlcude 1 of them, If all of them have value then include all 3 or if none of them have value then show 0?

Thanks for looking at this. I am dealing with both 0 and NULL values so I also need to account for that in the top box. The calculations for the 3 boxes below is perfect, works like a charm, I am struggling to roll it up dynamically!!! 

Amit

Amit Singh