FFS Merging of 2 Mfg Cells

We have Issue in model after Merging 2 Mfg Cells Successfully. So under one Main PPR we added 2 Mfg cells and using “Simulatable Children Cells” we are able to merge both the cells without any issue and model is running fine. But our requirement is between 2 Lines Inventory should be only 1. Currently its accepting infinite parts (though capacity of out zone is 1) . How to create this?