Kato makes a Unitrack double-crossover, their No. 20210:
Kato has advised us that this unit has four solenoids in its base, each operating one turnout point set.
Connecting the DS51K1 to the red / black wire pair at the base of the track will damage the decoder since the four solenoids of the crossover will draw more than the rated current capacity of the DS51K1.
If you are wiring the DS51K1 internally to this track segment, it is easiest to program each turnout pair to the same address; done this way, activating one track switch address will result in the operation of the pair of turnouts, or all four if you desire.
As an alternative, the DS64 can be wired to the red / black wire pair, with one address of the DS64 operating all four of the double crossover's track points.