You can create a stand-alone sketch and then create extrusions that copy parts of that sketch within the extrusions. You should generally embed the sketches in the extrusion feature to keep the model tree clean.

I'm sorry, but I'm confused, much appreciated for the help.

For example:
1) Sketch two circles next to each other then close the sketcher.
2) I'd like to extrude only one of these circles into a cylinder
3) Much later in my process I want to extrude the other circle from the same sketch into a cylinder

It appears when I go to step 2 in my process with Creo that it is forcing me to extrude both circles. I'm I missing something?

nx 9

Nope. You can create the extrusion, select to create another sketch; pick "Use Previous" for orientation, and then pick the edges you want from the existing sketch using the 'Project' sketcher tool. Any change in the original sketch will be reflected in the 'Projected' sketch internal to the solid feature.

I expect that SW does exactly the same process, but just hides the details from you, preventing you from otherwise customizing the usage of the original sketch, et al.

No one is forcing you to do anything; you are wanting to force Creo to do something it isn't designed to do.

i think that in swx you can select which part of sketch do you want to extrude (which circle).
i am not sure about creo though, but in wildfire 3 you can only select the entire sketch. i imagine creo is not a lot different.