How do I Move the ground in a set path?

In this platformer demo I'm working on there's a platform the player jumps to, and when that happens the ground just ahead of that platform will rise up fast, followed by the ground behind them rising fast. After both pieces of ground hit the top of the window screen I want them to move in toward each other (crushing any player who wasn't fast enough to get off the platform). After the pieces of ground collide, I finally want them to slowly move back to their original positions.

I've tried messing with the bullet behavior (editing the angle and speed in the event sheet as necessary), and tried just using the move at angle event. So far both have been unsatisfactory. Is there a simpler way to move objects in a set path?

That's a scripted event where two pieces of ground are moving twice, first Up, then Left of Right.

I would simply place three "DestinationSprites" where the pieces of ground need to go next (acting like targets), then having the grounds lerp or move toward them. I don't think messing with Behaviors is useful in this case...