Multivariate Time-Series with Differing Selling Windows
Welcome to the site! This is a fairly broad question and impossible to answer in a single post. So, I would have you start by researching recommender systems and algorithms. On top of that, if you fully want to take the stores into account, I would start collecting a dataset that contains attributes of each store - where are they? How many hours are they open? Do they have a lot of traffic? etc. 

If you proceed by using the products, then you would research a "content-based recommender system". If you want to proceed by looking at the stores, then you would research a "community based recommender system". From there you should be able to pick a model and/or choose a hybrid of the two approaches and develop a proper solution. 

Good luck!