Changing $IP$ for a NAT szenario

Hi,

a customer of mine uses DHCP for his Clients and like others 192.168.1.0/24 for his IP adresses.
To reach his clients I configured NAT.
Because the leases can change I want do use a DNS resolution to connect to the client via a dameware session.

The DNS naturally resolves an IP like 192.168.1.15.
Is there a possibility to change this with an script like
Host = Replace($IP$,'.1.','.20.')
?

Thank you for your help.
For me there are too many entry points for scripts (and I haven't used one yet) to see clear for what I can use them.
Coding would not be a problem.

Greetings,
Reiner