How do I make simple multiple user access app?

[Kurt Kaufman]

Hi Keith,
I designed a simple application to keep track of payments to ca. 1000 
accounts.  Originally I went with a single text file, parsed for the 
individual account data which was then loaded into fields in a single 
stack, but I had troubles getting the formatting to work equally well 
on Windows (I develop on Mac OS X).  I ended up using a separate stack 
for each account.  In addition, I have an account selection stack as 
well as a receipt-generating stack.  I use "busy[nameOfStack].txt" 
files as flags; they are created each time the selection stack, the 
receipt stack, or an account stack is opened, and destroyed each time 
the stack is closed.  There are 3 copies of the standalone navigation 
stack being used. When a second user wants to open a stack that is 
already open, a message pops up advising the user to try again in a few 
moments.
We are running this system at a medical office on a Windows Workgroup 
(peer-to-peer) network without problems.  I'd be happy to send you 
copies of the stacks if you'd like to see them.
You would have to make substantial changes to the account stack 
template if you needed to do things which required gathering info. from 
many or all of the accounts.  In addition, if you have many accounts, I 
can't imagine it would be very efficient to have to open and close so 
many stacks in succession. In that case a text-based or a SQL-based 
solution would be far superior.

HTH, Kurt