Hello Frank,
I tried installing the network and it worked however in order to install subsites on the www.miusa.org domain we need to change the main website from www.miusa.org to miusa.org and then subdomains will be a.miusa.org,b.miusa.org,c.miusa.org so on.
Let's discuss with the client if it's okay to move the website from www.miusa.org to miusa.org 