Sharing authority without creating a subdomain

[Steven Stromer]

Hi,

I am seeking to delegate authority for a few specific hosts, without 
placing those hosts under a subdomain. For instance:

Zone1:
domain.com, with records for...
www.domain.com
mail.domain.com

Zone 2:
ftp.domain.com
testing.domain.com


It would seem that I could create separate zones for each of the hosts 
listed under Zone 2, and then make each of these zones into children in 
Zone1, delegating and providing glue, as such:

ftp 86400 IN NS zone2_ns1.domain.com.

    86400 IN NS zone2_ns2.domain.com.

testing 86400 IN NS zone2_ns1.domain.com.

    86400 IN NS zone2_ns2.domain.com.

zone2_ns1.domain.com. 86400 IN A 192.253.254.2

zone2_ns2.domain.com. 86400 IN A 192.253.254.3


However, it seems to be a large amount of work, and just generally bad 
form to create a zone for individual hosts. Is there a better way to do 
this?

Thanks!

Steven Stromer