Custom stack sizes

Hello,

Does anyone know how to add custom stack sizes that override the stack multiplier values?
For example, I have a 5x multiplier on all item categories, but I want watter bottles, jerry cans and water buckets to not stack at all.

Alternatively, if someone knows how to make the above items stack while maintaining their existing liquid amounts.
So far, if you stack one ore more jerry cans, all of them except one will lose all liquid, which is annoying.

Thank you.

This is a known issue that's been in the plugin for years. It doesn't look like anyone wants to fix it.