301 redirects in multisite with non related sites

I’m moving a site that was not on WordPress into a multisite install that has multiple domains that aren’t related. I’m trying to create 301 redirects for pages from the old site as well as the subdomain that contained the blog. If I add them to the .htaccess file so that they look like this:

redirect 301 /aboutus/ http://newsite.com/our-story/

When someone tries to access /aboutus/ on any domain on the install they will be pushed newsite.com/our-story/.

I’ve seen several discussions in support about this, but so far none of them seem to come up with a solution or the best solution in the thread doesn’t work when I try it.

I’ve seen variations like the one below but none of them work.

<If “req(‘Host’) == ‘newsite.com'”>
Redirect permanent /aboutus/ http://newsite.com/our-story/
</If>

Has anyone actually managed to get this to work? Can you please share how you did. Thanks!