H1B Extension Using Existing 140 From Another Employer

[Prabhas]

Guys,

Please bear with me for posting this question here but your guidance to my current situation is much required.

My 2nd H1-B extension completes on Sept 30th -2012 and I am up for another Three Year extension based on the I-140 approved (PD July-2010 ) with my current Employer A .

If in any event my H1-B extension gets rejected with my current employer, I am planning to apply for an extension through one the clients that I previously worked with.

So in such scenario will this client ( Employer B) be eligible to file for three year H1-B for me based on a I-140 that is held/owned by Employer A?

Appreciate your advice in this matter.

Regards,

Prabhas