h1b transfer on approved I140 with 2 job offers

[tachyon007]

Hello,

 

Thanks in advance for reading through my post. I have a scenario that I would request your help

 

Valid I 140. H1B 6yrs completed. Current company got an extension until Dec,2015.

 

Now I have got an offer with another company "A" which is ready to port my GC application and start the Labor and Perm process.

 

I am also about to finish my onsite interview with another company "B" which is also potentially ready to redo the  Labor and Perm.

 

Company A offered me and I agreed as my talks with company B were going at a slow pace. They are about to start my H1B transfer process this week (6/25/2013). They want me to put in my 2 weeks notice after they get a receipt of the H1B transfer. Assuming the receipt would come in by say July 5th.

 

Now B wants to bring me onsite for final rounds of interview.

 

Career wise B is a better fit than A.

 

Under the hypothetical scenario::

 

I get offer from B and they agree to transfer my visa. Can I renege on the offer from A say around July 7th.

 

My concern is more related to can 2 employers file to transfer my H1B when I am under I 140 with my current employer??

 

The ideal situation is that I will not put in my 2 weeks notice until July 15th till which both the new employers will have sent papers to transfer my H1B under a valid I 140.

 

Is it OK, legally. Will my current employer know if some other firm has applied for my visa transfer with out me informing him.

 

Thanks for all your help.