We have a domain abc.com now we created a test domain xyz.com. is it possible to add xyz.com to abc.com DNS servers. if yes then please guide how?

Question

i added a domain suffix for exemple my domain is aabc.local that is in my active directory , i added the public domain abc.com .I created the dns zone abc.com in my AD with some internal reords that i need , it worked internally but for my public websites i coud not acces them from my LAN . Can you help me resolve this issue ?
i also checked this link , it did not help https://learn.microsoft.com/en-us/answers/questions/55359/how-to-add-other-domain-in-dns-server