Pg. 21 of the Zverograd campaign book states that each bomb can target one unit. Two bombs can be used to resolve the bomb as if it was a sustained attack action (note: bombs are not an attack action, they result from move actions.)
The SSU MIL MI-47D "Death Rain" has 2 bomb weapon lines with 2 bombs each.
The question is: Can this Aircraft drop it's entire payload on one movement action? Two bombs on two targets or one bomb on upto 4 legal targets?