How to move huge amount of folders to limited number of folders

Dear PS gurus,

I tried to searched my question online but didn't get what I need.Thanks very much:

Suppose there are lots of folders insides a root folder(namely, D:\) with different sizes (but all less than 4GB). I need to move them to limited number of folders(still in D:\, with name like group1, group2,...) but each folder must be less than 4GB. I use PS version 3 in Windows 7. Thx.