A family of Microsoft word processing software products for creating web, email, and print documents.
Mixing the different types of controls can sometimes produce unsatisfactory results and it might be better to use the procedure in the article "Making groups of Check Box Form Fields mutually exclusive (so that they behave like radio buttons)” at:
http://www.word.mvps.org/FAQs/TblsFldsFms/ExclusiveFmFldChbxs.htm
Note, it is not necessary to use a frame and if you have the checkboxes for each of the options in a single cell of a table, you can use
For Each oField In Selection.Cells(1).Range.FormFields
in place of
For Each oField In Selection.Frames(1).Range.FormFields