If ten men ate bread together, then before Birkat Hamazon they recite the Zimun with God’s Name, meaning, with the word "Elokenu." Hacham Ben Sion Abba Shaul (Israel, 1923-1998) addresses the situation of ten men who ate together, but only seven of whom ate bread, while the other three ate a Kezayit of fruits or vegetables. In such a case, he writes, the three who ate fruits or vegetables may join the seven who ate bread to recite a Zimun with "Elokenu." This applies as well, he writes, if the three did not eat anything, but drank a Rebi’it of a "significant" beverage, which Halacha defines in this respect as wine or natural fruit juice. If, however, the three drank only ater, or water with flavoring, such as tea or coffee, then they cannot count toward the required quorum of ten men to recite a Zimun with "Elokenu." Since water – or flavored water – is not considered a significant beverage, the three are not considered to have participated in the meal, and thus cannot count toward the Zimun.
Summary: If ten men ate together, seven of whom ate bread and three of whom ate a Kezayit of fruits or vegetables, the group may recite a Zimun with "Elokenu." This applies as well if the three drank a Rebi’it of wine or natural fruit juice. If, however, the three only drank water, tea or coffee, then the group may not recite a Zimun with "Elokenu."
