Hello, I am trying to create a formula which concatenates 12 adjacent cells
in a row but excludes any blank cells and puts a delimiting character *
between each instance. Please find a 4 column example below.

ID 1 2 3 4 Result
Z A C D A*C*D
Y B C B*C
X A B D A*B*D

This will be used in a 10,000 row Excel 2007 spreadsheet and each row is
potentially different - there are at least 5 blank cells on each row and
usually more.

Any help is gratefully received. Many thanks, Bob.