If you’re willing to drive about 30 minutes east or west of Fort Leonard Wood, you can join in the activities of the Rolla and Lebanon groups.
The Lebanon Area Homeschoolers (LAH) can be found at: http://www.lebanonareahomeschoolers.com
This website is not updated frequently as they now use Big Tent for communication, but this site is the best starting point to contact them.
Rolla has the Greater Rolla Area Christian Home Educators Support System (CHESS): http://www.homeschool-life.com/mo/chess
There is an annual membership fee for this group, which is currently listed as $10 per family.
If you’re willing to drive even farther, here are a few other homeschooling groups in Missouri:
Southwest Home Education Ministry (SHEM): http://shemonline.org
Christian Home Educators Felloship of Missouri (CHEF): http://www.chef-missouri.com
St. Louis Homeschooling Activities Resources and Encouragement (SHARE): http://www.homeschool-life.com/mo/share
Families for Home Education (FHE): http://www.fhe-mo.org