People who bought this bought those - Products Recommendations which is "in-stock" for the selected store.

We need to make Adobe Target recommendation based on cart algorithm - "People who bought this bought those". These recommendations should work using both online and in-store purchases data uploaded. However, we have over 16000 store and 25000+ products. Users can chose a store nearby. How do we show products recommendations which is "in-stock" for the selected store? How do we upload offline inventory data and filter the recommendation products?