All you need do is use some field coding to conditionally output the content that varies according to the number of shops done. As Graham says, though, without knowing the specifics, specific advice can't be given.
That said, there are plenty of examples of field codes being used to vary text in the mailmerge threads here and in the 'Sticky'
Mailmerge Tips & Tricks thread at the top of this forum (
https://www.msofficeforums.com/mail-...ps-tricks.html).