Question: it is possible to triple boot W7/W8/Fedora?
I was succesfuly booting on dual boot W7/W8, W7/Fedora and W8/Fedora.
Try to tripple boot also - on dual boot W7/W8 i install Fedora 17.
Bootloader on dev/sda(or C where i have installed W7.
W8 is installed on another hard drive(D or in Linux dev/sdb.
After Fedora installation W7 and Fedora run OK, but W8 not - i recieved a message that W8 must be repaired.
But none of the repair methods i trying was not succesful - W8 not start.

I think(with my limited Linux knowledge) that bootloader(Grub) installed on dev/sda corrupt W8 booting.
How to avoid this and where to install Fedora bootloader?

I hope that i am described situation well enough to understand what i want - please be patient, english is not my language.

Thanks for answers