drop down lists using a variable input

Hi,

this would appear to be a simple problem compared with my previous,
I have a user-input cell where the code options 'ALPHA' to 'FOXTROT' (1-6) can be used.
each code has a set of distances that maybe applied to it i.e. ALPHA may have 1km & 3km whilst BETA may have 1km and 2.7km
i've subbed in some simple values but this idea is that when the used puts the code 'ALPHA' into the top cell, the different distance options should be displayed in a drop down cell below - the user can then choose one of those.

my problem is getting a variable drop down selection depending on the input.

any help or a plan for doing this more efficiently would be appreciated
thanks, Doug.

This should help..

http://www.contextures.com/xlDataVal02.html