Hi Emmy,
It totally depends on what you're hoping to accomplish with this campaign, and how different your product lines are. At face value though, I'd generally aim to have different product lines separate from one another, as there are usually always some differences in how you message for each (and even if the flow is the exact same for all product lines now, it may change later). Running out of one big campaign can be pretty limiting when you need to make changes.
Just some food for thought.
-Jeff