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It is not what I have in mind. Anything goes, which does not break the initial conditions.
The initial conditions did not forbid dropping object A into a downdraft and object B into an updraft :-)
But here is another attempt: objects A and B open parachutes 3 seconds after passing altitude X. Object B starts at altitude X, accelerates from zero for three seconds, and then radically slows down. Object A starts higher, so when it passes altitude X it is already going fast and so in three seconds is capable of passing B which is already braked by a parachute.