Default value for drop-down based on column or calculated value

[David Jones 5]

I have a drop-down to select a well name from a column in my data table. Based on this well selection, I'd like a second drop-down to populate with a specific value related to that well.

Example datatable:

 

 

 

drop-down1 (wellname)

drop-down2

 

 

well1

a

 

 

well2

b

 

 

well3

a

 

 

well4

a

 

 

well5

b

 

 

 

When well1 is selected, I would like drop-down2 to show "a", but have "b" as the other option. If well2 is selected, I would like "b" to be displayed with "a" being the other option in the drop-down. I know what all the options will be ahead of time if that helps, I just want the displayed value to be the one associated with the well selected. Basically I want to display the current associated drop-down2 column value by default, but allow the end user the option to change to the other value.

Any ideas on how to achieve this

 

Thanks!