Differentiation vs. Cooperative Learning?

Today I spent 3 hours in a "workshop" about differentiated instruction. I got a lot of really good and immediately usable ideas for my classroom on doing work in groups, but I'm not always sure how some of the things I learned qualify as differentiation. When I use a strategy to create flexible grouping, for instance, doesn't that go against the differentiation idea? Shouldn't I be trying to group kids strategically in order to differentiate effectively? And on top of this confusion, I am finding it difficult to differentiate in a meaningful way since I am teaching a group of gifted kids aka homogeneously grouped. There is not much skill level difference among them, so I guess I'll have to try to differentiate more based on learning profiles, differentiate more process and product as opposed to skills. I get a lot of good data from the MAP test we use at school, so I am hoping that can help me do this right, but it seems daunting at times. Now I am faced with having to create a differentiated lesson to turn in and I have ideas about doing it with the unit on poetry I teach. I'm trying to decide how I want to approach this. Do I want to do something tic-tac-toe related? Menu options? Lit circles? Learning centers? Maybe it would help to see a differentiated lesson that someone else created and also see it in action in the classroom. All I know is that I want to do right by the kids I teach so I need to make sure I've got this down so I can be effective.