One of the most exciting characteristics of VBS is that it is a ministry that every church can make uniquely their own. LifeWay provides a wide variety of resources tailored for specific age groups from babies to adults, but we know that every church has unique needs and limitations that often requires adapting the resources to fit.
Broadly graded (either having all 1st through 6th graders in one class or having the same teacher rotate to different age groups) is a great example of a church needing to adapt the resources to fit the need.
When faced with the need to adapt LifeWay's VBS Bible study resources, consider using the resources designed for Grades 3 & 4. Since the age-appropriate learning activities are designed for the middle group, they will be easier to adapt up or down to fit all kids in grades 1- 6.