I'm not sure if I can be more specific, but I'll explain it from another angle:
Your current set up has it so that you player automatically jumps when it comes into contact with a platform.
My suggestion is to alter the jump strength just before the player hits the platform, so that when it makes contact it jumps up at a stronger/weaker strength than before. If you're mimicking DoodleJump your best bet is to the use a Y offset, so your event would read something like "at offset(0,10)".