fORM and multiple updates

I likely just need to be pointed in the right direction but looking for a way to update many records at once w/out getting a set and looping through each one, then calling store() which is expensive. Basically want to queue a bunch of UPDATE statements and execute all at once w/o writing my own SQL. Thoughts?

My use case is updating the order a collection of records where the order is not "natural" per se. Order is based on multiple column values.

Thanks in advance.