Dont' really udnerstand what the difference is between your
Group1 & " "=" "
NZ(Group1,""), which will return "" if group1 is null. In your case though, if Group1 is null will it not cause errors as you're not checking for null?
If you concatenate Null and the empty string (Null & "") you get the empty string. If you concatenate the empty string with the empty string ("" & "") you get the empty string. The result of the code is the same. The difference is my code does not call a function to get the result (Nz). I haven't tested it, but I believe my code is faster. By how much, I don't know. I suppose it is personal preference without any facts to back it up.