recording different drum patterns/kits within the same song

Hi - I am getting to grips with GA3 but I have come upon a stumbling point. Can anyone out there please tell me how to record different patterns and kits within the same song. I.e bar 0 - 24 pattern 5 from the blues for example and then bar 25 - 38 pattern 9 from the jazz section for example - and also how to choose a particular fill for a certain bar?. I have a song which needs a complete change of beat and kit but cant seem to understand how to do it. I think its something to do with the memory allocations is it? But cant understand the manual. :blush:
I run Cubase 4 studio on a pc.
Many Thanks guys.