Domainmapping working 90% as wanted

I have a multisite network at http://www.fariko.com
I have created a sub-site http://nl.fariko.com wich works fine on its own
I want to map http://fariko.nl in such a way that http://fariko.nl is still visible in the browser-adressbar. (in the background it should run on http://nl.fariko.com)
a page like http://nl.fariko.com/faq should also be available through http://fariko.nl/faq

I have full control over 3 Centos 7 VPS with WHM/cPanel. I also have a full-fledged DNS-control and can adjust any DNS-entry needed. (Which ofcourse can also be done with the cPanel-accounts itself.)

I have tried everything (i think) but all that worked was redirecting http://fariko.nl to http://nl.fariko.com which is not the desired outcome.

can you please advice what should work? (alias, addon, redirect, iframe redirect w/e) so that I know what to troubleshoot further?

again: the desired functional level should be: a page like http://nl.fariko.com/faq should also be available through http://fariko.nl/faq

thanks in advance
Alexander Korf