Basement with Bearing Walls

My foundation is complete and I have rock in the basement. Rather than using steel beams, I've opted for bearing walls where I have a grade beam for each bearing wall. My plan was to have the basement rough plumbed and floor poured before starting framing...since the grade beams are 4" below finished concrete floor. My concrete guy is out almost 3 weeks due to weather so I'm looking for a solution where I can start framing now. Basically, I just need a solution where I can install the bearing walls but I need a method to raise them 4" over the grade beam. Any ideas will be much appreciated.

Thanks in advance!