Show/Hide only specific hard drives on desktop and/or sidebar
You can use the chflags command to hide a drive icon from the desktop:

chflags hidden /Volumes/Hide\ Me


Then, relaunch the Finder by option-right-clicking it in the Dock and choosing Relaunch.

To restore visibility of an item, use chflags nohidden instead.

Of note, this won't hide the icon from the sidebar, only from the desktop and Finder folder listings.