I'm using drush site-install for my initial site, and everything works great, but when I go to try create another site (using table prefixes so I can use the same database), drush attempts to drop and recreate the database, so I loose all the table from my first site. I know how to target drush to a particular subsite, but I'm not sure how to tell the drush site-install command not to drop the database tables.
Is there a better way to do this if I want to setup a initial site with 2 additional sites?