If you are drop-shipping products on your site from different vendors, you could have shopping cart orders that are shipping from different origin points to a single destination.  UPSRateMonger now directly supports multiple origin zone tables for destinations worldwide. There are four steps to the process:

1. Somehow you must be able to figure out where a given item ships from, and tie that origin to a valid UPSR-generated zone table. The simplest way to do this may be to use the UPS CSV file name associated with a given product's origin zone. Thus, if you were shipping a product from Round Rock Texas, and that zone table is named uz_786 (the default), you might store the value ''786'' in the product record's database, or perhaps associate this number with the vendor record thats tied to a given product... exactly how you do it would depend on your store and how you manage this sort of thing. 
    
2. You must import the necessary zone table (see instructions linked in menu at left), making sure to leave the ''I am not using multiple origin points'' box UNchecked on the zone import form.
    
3. You must specify the optional origin zone parameter (instructions on how to do this are located in the documentation area of the UPSRatemonger.cfm template).
    
4. When calculating shipping charges incorporating multiple origin points you must call the tag once for each shipping origin point, as opposed to once for your whole shopping cart. Your cart software will have to be able to group shopping cart contents by shipping origin, make multiple calls to the tag as needed and finally tally up the resulting charges from these calls.