You can create a script which you can set up to run when you open the file, is that what you are looking for?
Typical script might be called 'OPEN' and need only consist of a single sort statement, just the same as your button.
(But of course this script can also include a number of commands - you might want to open your table on a particular layout, for example.)
Then you set this script to run on startup, which is set up slightly differently depending on your version.
In FM11, Click on File | File Options then click 'Perform Script' and select your script.