Snap symbol to a chord instead of to a note

I use the push and pull symbols for accordion. They snap to the assigned note in the staff, but I want them to snap to the chords above the note. Or at least, I want them to be above the staff, always on the same position.
I can do this manually every time I use these symbols, but it would be so much more convenient if they appear directly to the right place.
Changing the properties doesn't seem to work...
Anyone an idea how to make this work?