GRUB questions

[Bill]

Hi,

I have some questions about grub.  I have used dual boot without any 
problems for quite a bit of time but recently some questions have 
cropped up.

My system had Windows 7, and Mint Linux 21.2.  I use Grub to dual boot 
between Windows 7 and Linux.  I use Linux almost exclusively but keep 
Windows 7 around because I occasionally need some files and programs 
located there.  It's easier just to leave them there.  ( I never use 
Windows 7 for anything Internet related and a firewall prevents in and 
out internet traffic.)  Recently, I had a third hard drive with Windows 
10 installed on the computer. This computer is rather old and does not 
support Secure boot . Windows 10 works well on it but windows 11 will 
not work.   My questions are...

1. Can grub handle more than two hard drives?

2. The boot loader is located on the Windows 7 hard drive and I would 
rather leave it that way.  If I include the hard drive with Windows 10 
on the GRUB list, but the boot loader is not located there, is anything 
done to it by GRUB?    ( Explicitly the boot loader on the Windows 10 
drive. )

I can still access Windows 10 by changing the BIOS boot list at computer 
startup but using GRUB to switch between the three operating would be 
easier.

Best wishes,

Bill Stanley