Targeter to use for projectile splash/shrapnel?

I want to make something like napalm or a grenade. I need a Projectile to shoot other projectiles in a spherical radius, but the RLNTE targeter doesn't throw projectiles, it just creates their hits at various locations. It also does not activate if a block is hit, only when it hits entities.

So what targeter do I need to be using to simulate a splash/shrapnel effect?