Zone Files for Internal DNS Server

[Phusion]

I'm running BIND9 for internal DNS needs. Internally on the network we
have use DNS names for some servers. These only work internally. I
noticed a problem when creating a zone file. For example say I want to
forward requests destined for www.hotmail.com to an internal IP
address of 192.168.1.50. I created the following zone file. It works,
directing requests for www.hotmail.com to 192.168.1.50. The problem
lies when say I want to go to another website on the hotmail.com
domain like test.hotmail.com if there were one. Here would be my zone
file for hotmail.com.

db.hotmail.com
$TTL 3600
hotmail.com.   IN      SOA     ns.internal.com. root.ns.internal.com. (
                        20050909
                        3600
                        900
                        3600000
                        3600)

@        IN      NS      ns.internal.com.

www.hotmail.com.       IN      A       192.168.1.50

named.conf
zone "hotmail.com" in {
        type master;
        file "db.hotmail.com";
};

Let me know.

Phusion