A divorce judgment involving custody and support will be enforced across state lines. There is reciprocity between all 50 states. However, there is a process to make this happen. An attorney can aide you in registering your judgment in Missouri. An copy will need to be acquired. There are however requirements that must be met and you can discuss those with an attorney. You must have adequate contact with the state of Missouri.
Additionally, some very proactive clients ask if you can do this as a sort of housekeeping matter prior to any real issues arising. You can. However, most clients want to file an action immediately after registering the judgment, which is called a "foreign judgment". This might lead you to wonder if you need an attorney in the state of the divorce for the registration of the judgment and a separate one in Missouri for the custody or support matter. You do not. Despite the fact that the judgment is from another state, Missouri law is being practiced in order to bring it under the jurisdiction of the Missouri Courts.
Bottom Line: Find an attorney in Missouri and this is usually a short and relatively inexpensive process.