H1b visa stamping for employer A can I work for employer B

Hi friends here,

I'm staying out of US. H1b visa stamping being processed at consulate (administrative processing) based on petition with employer A. 

Now, employer B is offering H1b sponsorship (filing not start yet). Let's hope for the best, if the visa for employer A gets approved, and B's petition gets approved. Can I enter the US and work for employer B without amending employer B's petition? 

Thanks so much!

U must transfer the visa to Company B to work with it

Yes. Employer B will file H1b transfer petition for me. But it will be consular processing which means the I-797 approval will not have I94, because I am now out of US.

So if the H1b visa for employer A approved from consulate, I can enter US and work for Employer B given B’s petition approved, please?