Is there a way to alter the bowl game participants for the major bowls? I.E. how do I determine the tie in?

You would have to mod the bowls.xml file and adjust the order and conference id's.

Ok, I'm looking at it right now. I'm playing right now with "no playoffs" just bowl tie ins, I'm going to attempt to manipulate.

second question just out of curiosity, I notice the Peach and Fiesta are listed as the semifinal sites in the xml, will it alternate each year?

And thank you for the quick response!

No, they don't rotate... it just uses that list as-is.