multisite subdirectory redirect to another multisite

We have a multisite - http://yourlifeassist.co.za with multiple subdirectories (sites).
The - http://yourlifeassist.co.za/primecare site has changed it's name but they want to retain the 'old' URL for legacy users with an automatic redirect to the new site landing page -
http://yourlifeassist.co.za/groupfive.

Both sites;
http://yourlifeassist.co.za/primecare
and
http://yourlifeassist.co.za/groupfive
are present in the multisite.

What is the best method to achieve this?