Tying a bundle of arrows together one day got me thinking: Why not do the same with potions? This is the result.
Just tie them together!
This works for pretty much all common beneficial potions (Regeneration, Swiftness, Fire Resistance, Healing, Night Vision, Strength, Invisibility, Water Breathing), stacking 8 of them into one pack. (More would get in its own way.)
Additionally, you can use the same method to tie 8 buckets of Milk with some string together to make an antidote pack.