Is there a way to graph a chart by date (x axis) that shows stacked
bars for overlapping time?

Ideally, I would have the columns like below:

Date ShoppingStart TimeShopping
StoreAsStart TimeInStoreA
StoreBStart TimeInStoreB

1/1/08 7:00AM 5 hrs
8:32AM 45 min 10:00AM 1.5 hrs

Then you would see a bar for that date, with 1 big bar for the day,
with 2 colors inside that bar representing the time in shop a and the
time in shop b. The y axis would be hours from say 6:00 AM - 7:00
PM. Does this make sense? The Time in A and Time in B could
overlap. Any thoughts would be great!