🚀 go-pugleaf

Hi!
I'm currently setting up a db in FMP2 which is largely to make data
entry by a number of novices straight forward, chances are they won't
understand the data structure at all.
In a number of cases I have fields which have up to 50 pre-defined
values (although most are <20) to choose from. These categories are then
grouped into a smaller number of categories (3-5). What I want is to
have the data entry people only choosing one of the lower categories
(using radio buttons) and the higher one being entered automatically.
I've used a field defined as a calculation with a nested 'If' statement
like this:

If (Field 1 = "X" or Field 1 = "Y" or Field 1 = "Z", "It's one of
these", If (Field 1 = "A" or Field 1 = "B" or Field 1 = "C" or Field 1 =
"D", "It's something else", "Or it's nothing"))
 
This works fine but I'm concerned that a nested 'If' testing 50 cases
might be a bit big! Also, am I right in believing that this calculation
definition is stored once and only the result is stored several thousand
times once for each record?
 
Any suggestions will be appreciated
 
Ainsley