how to map a different domain that has the same IP

Hi I have 2 domains that are on the same host and so they share the same unique IP but they have different domain names. 1 is single WP install and the other, hijabmag.com, is a multisite install (in sub-directories /fr, /en). I installed this plugin hijabmag.com to map the multisite but can I install it also the other domain name to map them all together? thank you