Here's an idea, I haven't tested it.
You should be able to use the "Move at angle" action on the new objects when they spawn to move them away from each other in the direction you want.
"Move the object a number of pixels at a given angle in degrees."
You'll want to get the angle that the original object is moving, then add 90 degrees. Spawn the first new object and "Move at angle" with that new angle by the new object's width for distance. (Or perhaps half-width if it spawns on its center)
Then take the original object's angle again, and subtract 90 degrees. Spawn the second new object and "Move at angle" with this new angle, again by the new object's width for distance.
If they still collide, add a bit to the width so that they don't collide.
Alternatively, if you don't need the spawn placement to be variable, you could specify two image points on either side of the original object, and spawn your two new objects at those image points.