The easiest is if the player bounces only upwards.
Make a second ImagePoint on your enemy (Image Editor, second icon from bottom on the left, in the image point window press the plus icon) and place the ImagePoint on the top of your enemy (8 on the Numpad).
You need 2 events:
+ Player: On collision with Enemy
+ System: Player.Y < Enemy.ImagePointY(1) -> Player: Simulate Platform pressing Jump
If you don't want that your player jumps as high as the normal jump you can use vectorY:
+ Player: On collision with Enemy
+ System: Player.Y < Enemy.ImagePointY(1) -> Player: Set Platform vector Y to -250
Be aware that the value of vectorY has to be negative.
The second ImagePoint isn't really necessary. You could also use the origin ImagePoint, but you can get funny side effects if the origin ImagePoint is not in the middle of the Sprite.
If you use the origin you need only Enemy.Y
I assume that your player has the platform behavior and the enemy the solid.