Use Airburst logic with the secondary stage's Projectile having Vertical=yes, Ranged=yes, ProjectileRange=0 and AirburstSpread=.5 for delivering the damage to the indirectly-targetable types.
Use Airburst logic with the secondary stage's Projectile having Vertical=yes, Ranged=yes, ProjectileRange=0 and AirburstSpread=.5 for delivering the damage to the indirectly- targetable types.