Redundant data in zone file.

[bob prohaska]

Is there any harm in having redundant information in zone files?

For example, I've registered three domains: 
zefox.com
zefox.net
zefox.org

They must share 5 ip addresses: one for each nameserver in .net
and one for each www.zefox.com/net/org address. The netblock is
64.161.5.105-109. 

Will errors result if a zone file contains A records for hosts
in a different zone? It would simplify matters of all could share
the same zone file, but clearly that can't go on forever, if at all. 

Thanks for reading, and your help so far!

bob prohaska