Pure Play Question

Hey guys,

So here is the deal: I am new to finance and I am trying to learn how to compare a multi product line company with another using a pure play approach.

For instance, I am looking at JNJ consumer product line in which I have grouped: first aid, nutrition, and over the counter meds. I am trying to find comparable companies with a similar grouping. My problem is that I get confused when I find firms whose product lines include items that are outside of my “group”.

Where do you guys draw the line when it comes to pure play companies? What weighs in on your decisions in selecting similar companies?

Any advice would be greatly appreciated.