Ghost 15 with Mutliple Backup Drives

Using Ghost 15 with 2 external 1 TB drives - I use 1 drive each week and swap it out the following week

 

When I swap out the drive, Ghost gets confused and instead of looking at the external drive as a 'letterl - ie - E:, it looks at the dirve and gives it a name ("My Passport" for drive 1 and "My Passport  (2)" for drive 2)

 

The backup then fails

 

Is there a way to use 2 external drives for backup ?