Ghost 12 - Backup Destination designations

I have 2 external USB drives attached to my computer. One I bought specifically for the Norton Ghost backups (drive F). The other I use for media storage (drive G.)  Somehow Ghost 12 decided that BOTH drives are backup destinations - perhaps I failed to respond quickly enough or correctly to the dialogue that asks if you want to use the new drive as a backup destination - I'm not quite sure. The G: drive has never had anything backed up to it, so it's not like it once was a backup destination and now I don't want it to be - it never was.

 

Is there any way to convice Ghost 12 that my G: drive; even though it's an external USB drive; is NOT a backup destination?  As such, it keeps defaulting into most dialogue boxes as a backup destination, on the 'Status' page, and I am frustrated that I can't convince it otherwise.