Can an HD be mounted to two machines?

[Qwerty11]

I've got a 3TB external HD partitioned into two halved. The first half is the backup for my iMac. I was wondering if I could get some type of USB splitter that would allow me to mount the other partition to laptops at the same time.

Is this possible?

 

[Intell]

That is not possible. The only way to do it would be to have the drive shared over a network.