Depends on how "smart" you want your enemies to be..
Checking the position of each enemy compared to the position of the player and adding actions based on that would be the starting point..
By adding more conditions you could make the enemy smarter or dumber..
One idea would be to place detection-sprites at the ends of platforms and if enemy is overlapping and player.y<enemy.y have them jump down..
Jumping up and through a platform is only possible if there is a platform above, so checking for overlapping at offset (or any other way that suits you) and basing the jumping action on that could work..
Perhaps adding the timer behaviour to have the enemies "make decisions" at certain intevals would be of help (this could also prevent the enemies from going crazy)