Trouble figuring out multiple sites installation

I’m overhauling both of my sites, and I want both to run on wordpress (one’s an actual blog, the other isn’t but can still use WP as a CMS). I’ve had no trouble setting up the network installation and creating the sites (I’ve had to use sub directories, as my IX won’t allow wild card sub domains) or anything, my problem is figuring out the domain redirects.

I have my main domain name, dualitydesigns.ca, and I have 1 other domain, sketchandcode.ca. How to I have my links redirect from sketchandcode.ca to dualitydesigns.ca/sketchandcode? IX will only let me redirect a domain to one of my sub domains, not a particular directory, and I’m not sure if or how to write an htaccess redirect for it.