Use one external hard drive for both PowerPC and Intel backup?

[DewGuy]

I've currently got a PowerPC iMac (OS X 10.4.11) that I back up to a partitioned external hard drive using Carbon Copy Cloner. I'm thinking of getting an Intel Mac (OS X 10.5.6), would I be able to back it up to a different partition of that same external hard drive using either Carbon Copy Cloner or Time Machine?

End result would be one partitioned external hard drive with the PowerPC Mac backed up to one partition and the Intel Mac backed up to another partition, is that possible? Would/could both be bootable?

Thanks.