I think the game doesn't have a way to easily brings things together without it being like a secret Teleport. Both Repel and Knockback only seem to work away from the caster.
Mathwise, it's trivial to code "knock-towards" and "reverse repel" if you've already coded knockback and regular repel, you just swap the positions of the target and the caster in the formula. That might not translate to being easy to implement of course. But for reverse knockback, there'd be nothing to stop the target from simply flying over the origin point of the knockback and ending up farther away that it started.
But I'm not sure if the game engine can do that with the current implementation of the Knockback effect. It doesn't know where the knockback came from, only who the knockback came from, and it goes outwards from that direction. That's why if you throw Explosive Blast in to the middle of a group, even the ones in front of the blast point still fly backwards from your direction. I feel like knockback would need to be reworked in order to make it function another way. I would guess that reverse-knockback in the current engine would only be understood as knockback protection.
Explosive Blast works exactly as I described. It knocks the targets away from the caster (you).