Combat works like this:
Your first make your pile-in move up to 3" if you're within 3" of an enemy unit. Then you must declare ALL attacks beforehand. You can split the attacks as you like but because you declare it before actually attacking, you cannot say "now that this unit is dead, I'll use the remaining attacks on the other unit". It's a regular occurence that some of your attacks are wasted because you killed the remaining guys with 2 of your 5 attacks or whatever. After resolving any or all of your attacks, there is no second movement (like there would be in 40k)
Short answer: No
There's a similar situation in the Legions of Nagash FAQ
When Hexgorger Skulls wipe Endless Spells from a Wizard's memory, they relearn them because they're still there. Rules-wise Endless Spells aren't known by a Wizard in the first place but by your army. For the same reason this ability wouldn't work on spells of the realms if you're using the Realm of Battle rules.
The_Dudemeister's post in Pile in question was marked as the answer