If you wanted it to push them, Id imagine youd give the projectile an impulse
datablock ProjectileData(spearProjectile)
{
projectileShapeName = "./shapes/spearProjectile.dts";
directDamage = 50;
directDamageType = $DamageType::SpearDirect;
radiusDamageType = $DamageType::SpearRadius;
[b] impactImpulse = 1000;
verticalImpulse = 1000;[/b]
explosion = spearExplosion;
particleEmitter = spearTrailEmitter;
basicly add to impact impulse, and vertical impulse too if you want them to fly upwards.
To grab and move players, Id imagine youd have to mount it to the death vehicle, and then impulse it to other projectile explosions, which would have to explode in air, so the player would follow the bullets.
Thats just my wierd solution. Theres probably a better way.