How to choose boot order of multiple SATA drives

I have a Dell 9150. The original SATA disk has XP installed. I just added second SATA disk and installed Windows 7 on it.  I would like, during my migration period, to choose my boot drive at power up - there are still some tasks I can only perform in XP.

A BIOS setting would be OK for this, but there doesn't seem to be one to select the specific SATA drive to boot from - the only way appears to be by swapping cables around.E.g. to boot my new Win 7 drive (on SATA-2) I must disconnect my XP drive on SATA-0.

Is there a solution that does not involve cable swapping each time?