[iTunes] Large Music Library

[HSM]

Hi everyone,
Happy New year.

I have a large collection of music over 50 GB so far and is  
increasing. My HD is getting full , I have a 100GB external drive  
( maxtor) as a back up and another pocket size 60GB .

on my Maxtor i have a full backup of my Powerbook  HD , all  100 GB   
including my Itunes library

My Itunes on HD has one smart play list contains the "Least Played"  
tracks. That way i am always listening to the tracks i haven't  
listened to for a long time.

Due to space limitation and because i have a full back up of my  
itunes library, i deleted 10 GB of music tracks. since then my free  
space on HD is down to about 5 GB. Consequently, i cannot restore my  
itunes anymore ( no space left on PB)

Is there a way i can only "import" from Maxtor or from my pocket HD   
the least played tracks.? I know i can sort them by number of times  
played, but how will i move or copy to  PB library?

is having 2 itunes library on one machine/ hard disk possible.?  will  
it help.?

thanks