Users are successfully crushing 5 to 8 pills at a time in the pouches. More pills usually requires more flushing cycles after the meds are crushed to pass along the medication from the pouch. Flushing the contents of the pouch is achieved by filling the syringe with liquid, injecting into the pouch, shaking and removing contents multiple times until all dissolved medication is captured.
The question of crushing multiple medications in the same pouch at the same time, is covered in an article by Matthew Grissinger. (see citation below).
As of 2/28/2022 every pharmacist surveyed from among RxCrush customers, recommends that only one medication be crushed in a dose. Several pills of the same medication can be crushed for the same dose, but not a mix of different medications.
Grissinger M. Preventing errors when drugs are given via enteral feeding tubes. P T. 2013 Oct;38(10):575-6. PMID: 24391375; PMCID: PMC3875244.