using a set of values

[anders alm <anders alm home se>]

first of all i just wanted to thank all developers participating in the cool
gnumeric project!

but i have a little (prolly trivial) problem i'd really apreciate if i could
solve... let's say i wanna try out some different sets of values, like on
a1-a25 i have one set, and on b1-b25 i have another etc.. how can i make it so
i only need to change one value (somewhere) to get access to each set? 

to simplify my problem i'd like to do something like this: 
define SET = 'b' 
to get access to the first row in that set i'd use something like =${SET}$1
etc... 

some kind of solution would really save me a lot of work later on... =) thanks
in advance, i hope u can help!