How to select multiple waypoints

I made a detailed mission in Mission Planner. This mission had the option checked to apply terrain following. Mission flew perfectly using Mission Planner. Mission was saved as a .waypoints file which QGC is able to load. When I import the mission into QGC there is no terrain following and the waypoints all default to above mean sea level. How can I select multiple waypoints in QGC to apply the Altitude Above Terrain option to each waypoint? Thanks