Here's one approach using data table subscripting (needs JMP 13); it depends on the table columns being identically ordered.
dt = Open( "$sample_data/Big Class.jmp" );
dt2 = subset( dt );
dt << select rows( {2, 4, 6} );
sel = dt << Get Selected Rows; // [2,4,6]
seldata = dt[sel, 0]; // {{"LOUISE", 12, "F", 61, 123}, {"J...
oldend = N Rows( dt2 ); // 40
dt2 << addrows( N Items( seldata ) ); // add 3 rows to end
// copy the seldata to the end, one after the old end
dt2[oldend + 1 :: oldend + N Items( seldata ), 0] = seldata;
Here's an approach using concatenation:
dt = Open( "$sample_data/Big Class.jmp" );
dt2 = subset( dt );
dt << select rows( {2, 4, 6} );
dt3 = dt << subset( Selected Rows( 1 ), Selected columns only( 0 ) );
dt2 << concatenate( dt3, AppendToFirstTable( 1 ) );
Craige