Combining SWF files and sharing resources newbie question ..

I'm sure this has been asked and answered many times but after
scouring groups and the web I am still stuck.

I am using FLASH 8.0 pro on windows XP. I need make a bunch od
animated cartoons synched to a soundtrack.
They average around 15 minutes each and are somewhat graphic and audio
intensive.

I understand that splitting them into 5 different SWF's and using
LOAD( ) is a way to do this but I must be missing something.

In the end, they must run back to back with no gap as if they are one
movie and share the graphic and audio resources so as to minimize the
alteady huge file sizes.

What is the best practice here?

Danny