Crystal Reports Seperating fields in a text box with a comma

Message

     I have a text box with embedded formula fields.

This is a sample of the contents:

Based on these results, We have determined that you can benefit greatly from using our {2@111} {3@222} {4@333} {5@444} {6@555} {7@777} Services.

Each of the formula fields are based on an if then statement.  If true it includes the "Text" otherwise it doesn't display anything.  I want to add a comma after each field if it is present in the text box and there is another formula field included.

Here are some examples of what I am hoping for:
Based on these results, We have determined that you can benefit greatly from using our 111, 444, 777 Services.

Based on these results, We have determined that you can benefit greatly from using our 222 Services.
Based on these results, We have determined that you can benefit greatly from using our 111, 222, 333, 444, 555, 777 Services.

Thank you for any assistance you can provide.