Hello ozsenior, welcome to NeoSmart Technologies.
Just install Linux first, and during setup, make sure to tell it to install GRUB to the boot sector of a partition and *not* the MBR.
Then install Vista. Install EasyBCD in Vista, and tell it to add a Linux O/S with the drive/partition = to those you installed GRUB to.
You can install as many other Linux distros as you like without a problem, just make sure to tell the setup to install GRUB to the same drive/partition as you did the first time around, or else your configuration will be overwritten.