Multiple selection (range or individual) capability in a drop down list
 

Does it take code to do a multiple selection (the same behavior as
most MS products: LEFT, move down, SHIFT-LEFT for a range, or LEFT,
CTRL-LEFT,CTRL-LEFT,,, for individual items) in an Excel drop down
list?

The list in question will contain 8000 data points, and multiple
ranges need to be specified for side by side comparison..in this case
ranges of hours on a series of days. One could see how this might get
tedious if the selections ended up being a hundred or so which would
be common.

I've looked at the DV0017 on Contextures (much appreciated, thanks
Debra), but it doesn't support the desired behavior. The list must
stay in focus while the multiple selections are made.

Is this possible?