Toppling Spell (Metamagic)

[The_Jette]

Okay, so Toppling Spell is a metamagic feat that only applies to force spells, and adds +1 to the spell level. It goes that if the target takes damage, fails a saving throw, or is moved by your force spell, you get a free trip attempt using your caster level plus your ability modifier. But, it's not very specific past that. So, if are a tenth level sorc and cast magic missile (5 missiles) and target five different people, one for each missile, do you get a trip attempt against all five? Or, do you only get a trip attempt against one of them of your choice? Or, do you only get the trip attempt if you target all five missiles at the same target? Or, one further, if you send them all at the same target, do you get one trip attempt per missile? If you can get a trip attempt against each target, but not multiple attempts against the same, what would be the advantage of targeting the same creature with that magic missile?
Has anyone run into this problem before?

[redwizard007]

Okay, so Toppling Spell is a metamagic feat that only applies to force spells, and adds +1 to the spell level. It goes that if the target takes damage, fails a saving throw, or is moved by your force spell, you get a free trip attempt using your caster level plus your ability modifier. But, it's not very specific past that. So, if are a tenth level sorc and cast magic missile (5 missiles) and target five different people, one for each missile, do you get a trip attempt against all five? Or, do you only get a trip attempt against one of them of your choice? Or, do you only get the trip attempt if you target all five missiles at the same target? Or, one further, if you send them all at the same target, do you get one trip attempt per missile? If you can get a trip attempt against each target, but not multiple attempts against the same, what would be the advantage of targeting the same creature with that magic missile?
Has anyone run into this problem before?

RAW: one trip per missile.
RAI: probably need to target a single creature with a single trip. Other missiles have no additional effect. Otherwise, that +1 spell level is a little light for balance.