H1 transfer while a transfer is already in process


Currently i am working with Employer A who transfered my H1b in regular processing . I started working with them on recipt notice. Now i have a offer with Employeer B and i want to join them , Is it possible for Employeer B to apply for my h1 transfer while one transfer is already in process.

If yes , then what can be outcomes or anything i should keep in mind.