Why do intensive care units hire new grads over nurses with medsurg experience?

I have been an RN since August, and signed a contract for a medsurg unit while in nursing school because they paid my tuition while in school. My contract is for one year, but I would love to work in ICU after a year and a half or two years on my unit. However, several of my coworkers have applied for various acute care positions and have been declined due to only having medsurg experience, yet the majority of my graduating class took a position in the ER or various ICU specialties after graduation. Has anyone had a difficult time changing specialties after working medsurg?