Thanks for your reply
I think the answer to which one will show (or be allocated the click) is the one that offers the highest combination of click thru' rate x cpc - that's how google differentiate when there is the possibility of them serving an ad from more that one adgroup.
Why do you think it's pointless? Because it's not possible to do or because there's no meanigful info. to be had from doing it, or something else?
I thought if [blue widget] got a better return than blue widget then I could bid accordingly on these 'two' different terms - does you think I'm wrong :-((