DNS ZONE FILES - REVERSE ZONES QUESTION

["Uri Zalk" <uri@xxxxxxxxx>]

How do I set up reverse zone files for sub-networks?

I need to move DNS for a domain currently controlled by an ISP 
to a server.controlled by the domain owner.

The domain only has a sub-networked block of IP's

(Fictitious "Private" IP's are substitued for the real
"Public" IP's to ensure confidentiality in the example).

Say the domain is some.co.za and the IP block is
192.168.1.0 netmask 255.255.255.192

i.e IP 1-62 with 0 network and 63 broadcast address.

the next block is
192.168.1.64 netmask 255.255.255.192

i.e IP 65-126 with 64 network and 127 broadcast address.
This block belongs to another domain etc.

What is the proper way, if any to define the reverse zone file.

Had the domain owner controlled 
192.168.1.0 netmask 255.255.255.0

the reverse zone would have been

"1.168.192.IN-ADDR.ARPA."
with PTR records from 1 to 254.

Now the domain owner does not control the whole of the 
192.168.1.0 network.

The forward "zone" file will be "some.co.za" and the reverse

would have been, say "192.168.1".. No matter what we call
them we will have more than one domain purporting to
control and be authoritative for "1.168.192.IN-ADDR.ARPA."

On the the other hand, if we create a reverse zone file using
other than, say "1.168.192.IN-ADDR.ARPA.", for example,
"1.1.168.192.IN-ADDR.ARPA." zone transfer and updates
will only work for 192.168.1.1 and not for the whole sub-network.

Is there a correct way to deal with this situation?

I tried reading all the FAQ, HOWTO and any other relevant
info I could find.

Can anyone point me in the right direction?

TIA

uRI