H1 transfer with direct client and client's prime vendor for same position

[ajain5]

Hi,

Is it legal to file H1 transfer for a position via 2 employers , i.e. direct client and the client's prime vendor, to be on safer side. The 2 applications can be filled, either simultaneously or a week apart.

I have an approved I140 and my present H1 is valid till Oct/2017.

Thanks