Skill Planning

Conceptually, I'm having a lot of difficulties here. If all that somebody wanted was to create a plan for one single skill, no problem. But people are obviously aren't going to limit it to one skill. If someone wanted to add several unrelated, i.e. don't contain overlapping skill and level requirements, then there still isn't a problem. However, situations that contain overlapping skills is where I'm stuck.

I've pretty much spent my entire day conceptualizing and drawing diagrams. There are just so many scenarios that its frying my brain.