Not quite... the host-node map maps something like
www.my-domain.com
to a subsite (or URL) such as
/my-domain... i.e. it maps to www.real-domain.com/my-domain
Therefore you can have different URLs point to the same AOLServer instance, but when request hit the site, the host-node map directs them to the appropriate subsite based on the URL they requested.
so, you could have three subsites mounted as
msite.com/
/sub-1
/sub-2
/sub-3
with sub-one.com mapping to sub-1
sub-two.com mapping to sub-2
and
sub-three mapping to sub-3
then if someone went to www.sub-two.com they'd actually end up at your subsite i.e. /sub-1
Cheers
Simon