forward zone - FQDN

[#1]

Have an intresting one.

Have a request to forward / deligate a zone to an external partner, however the partner is using NS records for their nameservers.

for subzone.domain.com -> I want our infoblox to recursely querry dns.otherdomain.com & dns2.otherdomain.com.  The partner who owns otherdomain.com perfers for us to querry the server based on hostname, and not IP address, as they may and will change them.

Am I missing why I can't do this as a forward zone?

[#2]

"forward" zones can only use IP addresses.