Working end grain always seems to be hard work even on kit like Wadkin EQ spindle moulders (got a soft spot for them beauties ;D )
The way I reduce the chatter or push away that I think you allude to is by using a sliding carriage/jig that allows the piece to be clamped down to it while the slide groove in the table or the sliding table prevents push away. This often means setting up with a sub table the same thickness as the sliding jig for the stile moldings (these are pretty common in w/shops anyway as a means of running small moldings over the large opening the cutter block rises through). This is also a safer method of work too.
Rob.