Southwest Four Wheel Drive Association (a Member Organization of UFWDA) covers MO...http://www.swfwda.org/Member_Clubs.html
On of their member clubs is below although that is a little far from St Louis. You might e-mail them for more info and see what they know about anyone closer to you.
Ozark Mountain 4x4 Club, Inc.
President: Zach Summers
P.O. Box 4491
Springfield, MO 65807
And someone else with more info about MO may post up as well.