Complex spreadsheet

Ok... So I have an idea for a spreadsheet but not quite sure if it's possible. I work in the grocery business and one of the hardest orders to do is a milk order. To do a good order it would be much easier to have history from several like events. We run gallon milk on sale... Either main brand or private label... And sometimes we have no milk on ad. So my idea is to compose a spreadsheet that will contain a year or more of data on separate pages and each page would be named with the milk on sale and the price of the milk. When doing a new Order you would be able to input the price and brand in sale and it would draw info from like ads and take an average of 3-4 like ads... Or take an average of no milk on ad. It would need cells to calculate what was ordered and what was sold to get an accurate figure. This spreadsheet would used to order 50+ dairy items. I guess my question is... Is it possible to take an average from several sheets and can excel determine which sheets to pull from if named properly? Any help is appreciated! Thanks!!