If you need to do a conditional in your .htaccess you can use something like the below (example based on getting a htpasswd file):
<If "req('Host') == 'example.com'">
AuthUserFile httpdocs/.htpasswd
AuthType Basic
AuthName "Password Protected"
Require valid-user
</If>
<If "req('Host') == 'example2.com'">
AuthUserFile httpdocs/.htpasswd
AuthType Basic
AuthName "Password Protected"
Require valid-user
</If>
<Else>
Require all granted
</Else>
If you have any trouble with your .htaccess please feel free to drop us a line and we would be happy to help.