at frame 1 put in an "loadmovie( "the1.swf", 1)" in the
main.swf and on the first segment movie at the last frame put an
"loadmovie( "the2.swf", 1)"
This will cause the movies to load on top of the main.swf and
by putting the as on frame 800 of the first external movie you can
condense the main.swf into a 2 frame show where the first frame is
the "loadmovie" and the second is a stop.
This is because the changing to the second movie is handled
in the first external swf
As a side note if you dont wish the main.swf to show through
just change the "1" to an "0"