We purchase a product in grams but it comes in difference packaging sizes: 500g, 1kg, 300kg, etc. Sometimes we need to transfer x grams from a larger jar into another container. These packaging sizes are currently set up as UOM. Is there a way to track the stock on hand per container?

How many jars you have. Maybe consider them as a bin and then use bin to track the balance but make sure if you use bins you’ll have to select them in inventory movement.