Forcing markers in ar_track_alvar to lie in the same plane

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Hey!

I want to attach several markers to a wall to get an accurate transformation between the wall an my camera.

The at_track_alvar package already contains support for marker groups so I'm looking for a way to encode the constraint that all marker lie in the same plane into the pose computation. I don't know how the patterns are located on the wall, I just know that they have the same normal vector. Is there some way to integrate this constraint?