The rav came up with a brilliant solution: In my case, it was a set of six glasses. He said I should (with permission of the store owner), switch each one the glasses in the toveled set with one of the glasses in another set. That way, anyone buying any set will have a majority of glasses which need tevilla and thus will not make a brocho levatala when toveling them.
There is no problem here of bitul issur lechatchila since there is no issur to tovel a dish which was already toveled, and although it is ossur to make a brocho when doing so, but this would not be called an issur on the item, just a general issur of brocho levatolo.
A question could be asked in an opposite case, where one had a majority of kelim which WERE already toveled and he intentionally mixed in one which was not yet toveled, would this be called mevatel issur lechatchila?
On the other hand, the bitul would not work to permit the use of the Keilim w/o tevilla. This is based on the Oneg Yomtov who writes that if tzitzis that were not made lishmo got mixed up with a rov of tzitis that were made lishmo, the non-lishmo tzizis would not be butel, since bitul only works for ISSUR to make it muttar, but CANNOT add a POSITIVE status to something, Therefore the non lishmo tzitis could not get the status of lishmo through bitul.
The same would be with keilim which were not toveled, since as we said before, the need for tevila is not an issur but a mitzvah, the non toveled dishes could not get a toveled status through bitul.
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