You pretty much can't, for the most.
However, what you can do is search for the scheduled departures out of PANC, and see where they are headed. Search for PANC (Anchorage Int'l), then click on 'more' in the scheduled departures section. From there you can sort by destination.
So far, it appears that all of today's UPS flights are headed to KSDF. Yesterday had 2 flights headed to KONT.
EDIT: If you really want to get into it, you could hit up LiveATC.net and actually listen in on ATC, from when the flight calls up for clearance, all the way through the departure. PANC, KONT, and KSDF all have feeds, so you could listen to them as they depart and land.
BL.