Create Custom DNS for Resellers

I am new in server managment by directadmin and now I want to create custom DNS names for one of my resellers ...

For exmaple if my server works with
ns1.server.com
ns2.server.com

I want to create DNSs like
ns1.reseller1.com
ns1.reseller1.com

and let reseller1 web site to work with this new DNS names ...

My Server have 5 IP address and if it could be possible I want to set new DNS to work with one of this IP numbers ...

I will be glad if you help me to do this ... I tried to do this before but could not succed ...

Thanks and sorry because of my poor English ...

The Search Tool is your best friend

If you make a 'Search' for 'Custom DNS' yo get one interesting link:

HOWTO - provide sites with private nameservers, without additional IP addresses

Hope this help you,
Regards

Thanks for your reply ... but what I have to do if I want to use free IP numbers to set for new DNS's !?