pathfinder – When grappling multiple creatures, how many grapples do you launch?

Various abilities allow creatures to attack more than one other creature. Some examples:

  • Mimics automatically attack anyone they strike during a Slam attack, unless they dissolve their adhesive (Ex)
  • Creatures with the ability to capture can take -20 to not have the Grappled condition and potentially take other creatures even before their next turn.
  • A creature caught with another could be seized by a third party and try to reverse this grapple

When you try to hold (or invert) a grappling hook, can you launch for all the grappled creatures at once? Each creature grappled in one action? Or can you only grapple one (two / three if you have a top and / or quick grapple) and drop the others?