Supporting Multiple CNAMEs for a Domain

[Will]

How do you support multiple CNAMEs for a host - to support round robin - in 
BIND 9.3.0?

When we insert this into the zone file it fails the zone:

    test    CNAME    www1.domain.com.
               CNAME    www2.domain.com.

Simply commenting out the second CNAME the zone works again.

-- 
Will