I have created a python script that runs an OD cost matrix over five years, from 1999 to 2004. I have set up an OD cost matrix for each year, which I think is very cumbersome. Is there someone who can show me how I do this with a loop in python (arcpy) instead of setting up the OD cost matrix for each year. In my orgins and Destinations I also have a field called HOSPITALS. In the OD cost matrix, this field should be connected to each other so there will only be an analysis of each orgins to Destination. How is this done?