H1B transfer question

I am now a postdoc with a H1B visa. Because the present lab is not suitable for me, I am trying to transfering to other labs. I found a lab in University A which was willing to sponser my H1B transfer.The H1B transfer application is still pending. Now I find another better lab in University B. My question is: can I file another H1B transfer petition by University B at the same time without negative effect on the approval? Should I cancel the first H1B transfer petition before the second H1B transfer? will the cancellation have effect on the second transfer petition? I would appreciate your precious advice.