How to consider da whole MC ?HELP plZzzzz

hi every 1 …

   i hav a small prob..regarding moviclip ...im doing a flashMX car game .. where ,when da obstacles hit da car ..da obstacles disappear...the prob here is ...the obstacles disappears only when it passes by the center point of  the car(which is a MC)...So i need  a code to consider the whole car(MC) as a single object so tat whenever any obstacles touches any part of the car, it disappears........ CAN ANY 1 PLeASE HELP MEEE........... 

ill be very thnk full…

thank you in advance …
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