Hi Cindy,
Disney never guarantees connecting rooms. However there are situations that get prioritized, such as families with more children than adults (like you) or guests with medical issues where a caregiver may need immediate access to a room. I can tell you that my family of five almost always requests connecting rooms. In dozens of trips, we've only once not gotten the rooms connecting.
To increase your odds of getting connecting rooms, you should confirm your request a week before your arrival.
My friend Bret discusses how to do that in another Moms Panel post.
If you're still worried, you may want to consider booking a family suite at the All Star Music resort or the brand new Art of Animation resort. These are basically like two value rooms stuck together. They sleep up to six people, have two bathrooms, as well as a small kitchenette. These are perfect for budget-conscious families of five or six people.
Good luck with your planning. Please let us know if you have additional questions.