i dont think they do in the way you're thinking, but my best advice would be to call. we have a block of discounted rooms reserved for our wedding, but there are guarantees associated with it and a pretty hefty penalty if we don't meet it. And the minimum number of rooms was 10.
This is from Disney's website:
For groups with 10 or more rooms, please call (407) 828-3318. If you are under 18 years of age, you must have your parent or guardian's permission to call.
So i think with 4 rooms, you wouldn't qualify.