This isn't too tough of a task. Rather than use an array, I would use a string and concatenate each new value to the end of it.

Global StringVar IdList;
IF IdList == "" Then
    IdList := {table.IdField}
Else
    IdList := IdList + ", " + {table.IdField};

I cover all the Crystal Reports built in functions and give code examples like this in Chapter 6 of my Encyclopedia book. You can find out more about my books at Amazon.com or reading the Crystal Reports eBooks online.

It is working! Thanks very much :-)