The wording for a family unity sand ceremony depends on whether the couple wishes to exchange vows between the families or if the officiant alone speaks. Either way, communicate the symbolism of mixing many containers into one just as the families that were once separate are now one.
If the families exchange vows, the officiant can ask each person with a container or each family about committing to the family and sharing the future together. These statements can be the same or specific to the family members. One example would be to address the bride's family and groom's family individually about honoring the new bond that is created between the families from the marriage and then ask them to affirm their commitment.
Whether there are vows exchanged or not, the officiant can describe the significance of the ceremony and explain what each color or layer symbolizes. If each person in the family has a different color, the officiant can talk about how each color stands for the foundations of the family. When the final layer is created by mixing the sands together, he can explain that the family cannot be separated just as the sand cannot ever be separated again. The officiant can also explain each step or narrate the ceremony for the guests.