Edit and add the following to the VMX file :

scsi1.present = “TRUE”
scsi1.virtualDev = “lsilogic”
scsi1.sharedBus = “virtual”
disk.locking = “false”
scsi1:0.present = “TRUE”
scsi1:0.fileName = “Shared.vmdk”

Notice that the SCSI target is 1:0 and not 0:1

After this you should be able share the disk between 2 VM’s.