I have a need to design an ip address inventory for about 10,000 network
assignments.  

Here is how it I think it would be setup.  
One table preloaded with network info and a ID identifier.  TX1, TX2, CA1,
CA2 which is unique for each assignment.

One table where I enter in location info - San Antonio location, with TX as
identifier for state.  
A form when I enter TX as the state identifier, it pulls the next available
record in the ip address table and assigns it to this record automatically.

I was able to do a form where If I knew the identifier  (TX1) and entered it
in, it properly pulled the network and associated the records.  I just cant
do it automatically.  Any simple ideas for this?