This is something that I hope is not just in my mind I want to do. What I'd
like to be able to do, is have a drop-down list, and when an item is
selected in that list, it not only puts that item into the cell, but also a
corresponding value into another cell. Here is an example:

Choice Data
x 12345
y 24680
z 13579

In this case, the Choices would be in a list. When I select "x" from the
list, it puts the value "x" into its cell as well as "12345" into an
adjacent cell. If anyone knows what to do, I'd appreciate some help on
this.