How would one actually calculate the full “fruit of labor” in work that includes several people doing different tasks?

How to calculate between people doing the same task producing physical items seems easy. Add in customer service, sales, and development, and it seems easier to focus on what other groups pay for those skills, which is not what I want.

It also seems looking at the difference between having the role, and not. However some skills are mandatory, just less involved.

Feel free to simplify, but different tasks is a must.