I'd like to ask for help in the following problem:
col A contains alphanumeric values of different lenght (<20 characters) made
up to describe a different number of properties. Col B contains "key"s (also
alphanumeric).
I'd like to check, wheter the first part of a key of given (in D1) lenght
is included in any (which) of Ai (the proprties descriptor) and for how many
items the given key can be used.
Example:

colA: ColB:
rgt3huw57jfuhu; huw5cf9;
huwz57jkrt; 57jf8ac5;
o7jf800f; uwz5j9;
rgt8huw6hzz;....... 7jf8kol;........
if d1=3 then b1 will open a1, a2,and a4; b2 will open a1, a2; b3 will do
only a2; b4 will do only a1 and a3
if d1=4 then b1 will open a1, a2,; b2 will open a1; b3 will do a2; b4 only
a3.
Any suggestions ?