Hey, I recognize that race. That was a Sunday in Warwick, RI this past December, right?
As far as triathlons goes, are you mostly into the sprint variety? If so, I think you could probably do all right with a regular CX bike with some road tires on the thing. I'm no triathlete, though, my gf is into them. I use my CX bike with road tires for a rain/off season commuter bike. I think you'd be fine, especially for sprint triathlons, and I can't imagine not using a specialty bike would cause you to lose more than a minute or so off your 17 mile sprint bike ride...but, here' I'm assuming a shorter sprint-length triathlon...if you're into longer road races, I'm not as sure of an answer.