Q:

Using Grub for Different Drives

I have a HDD which has windows and ubuntu installed on dual boot and it works fine. I have decided to install a new SSD in my system. Now I know this SSD will also have at least one OS installed on it.
I know that you can manually install grub on each drive but I want to know what is the best way to go about it. 
Is there a way I can get a single menu at boot listing the OSes from both the disks?
PS: I am new here, so guide me where I should ask this if not here

A:

Is there a way I can get a single menu at boot listing the OSes from
  both the disks?

Yes. When installing on your new SSD, you can either have it install GRUB to your HDD (replacing the GRUb currently on there), or you can just have it install to your SSD. Either way, it will detect all of the operating systems. (And if it doesn't you can make it detect them by doing sudo update-grub
However:

Make sure you install in the same boot mode as your other OSes! So if all of your currently installed OSes are installed in MBR mode, then install to your SSD in MBR mode. Likewise, if all your OSes are installed in UEFI mode, mkae sure to install in UEFI mode to your SSD
Also note that installing Windows after Ubuntu will nuke GRUB, so make sure to install Ubuntu after Windows.

