H1B Multiple employer Transfer

Hi ,

I am working for company A which has valid I94 till Sep 2019.

I got offers from Company B & C at same time .Accepted B and started Premium Processing few days back.

Now , due to my wife got the job in location in same city as C.

So , can i start h1b process c also in parallel now which will be normal.

Till it get approval , can i work for B and move on to C , when it gets approved? or i need to reapply for transfer after B is approved.

I need to work for B , till i get C is approved.

Please let me know what is right way of doing it.