The process wold look something like this:
Names Default To Here( 1 );
// Input your new data
dt = Current Data Table();
// Open the cummulative data table
dtCummulative = Open( "path to the saved cumulative data table" );
// Add the new data to the cumulative data table
dtCummulative << concatenate( dt, Append to First Table( 1 ) );
// Save the new version of the cummulative data
dtCummulative << Save( "path to the saved cumulative data table" );
// Delete the cummulative table from the JMP session
Close( dtCummulative, nosave );
Jim