[911nut]

I'm a decent time trialist (my bike times are usually in the top 5% in duathlons; too bad I run like a sloth) but there's some guys that have a genetic advantage for cycling (big heart and lungs) and they gravitate to the sport. Don't compare yourself to them, just work on your game.
If you are riding with guys who are all on road bikes, you will be at a disadvantage with the wider tires that are on a hybrid (higher rolling resistance). Also, a nice, light bike like a Marin will help you on a hilly course.
If you have the spare cash, buy a set of deep aero section wheels (like Hed Alps or Mavic Cosmic Carbones). The reduction in drag will let you ride faster with less energy output. That will enable you to hang with the group longer.
Car racing is similar at the highest levels, I imagine.