Welcome to the UA/CO forums, from one former STL-er to another!
You can indeed match your UA elite status for elite status on CO by linking your frequent flyer accounts, see this thread for the link:
http://www.flyertalk.com/forum/unite...tus-tools.html. Do it now -- it's easy, and will probably benefit you in terms of potential upgrades from IAH, where you likely to be booking CO flights. Mileage can now also be transferred freely between the two programs, and will be combined when the two programs fully merge, so which airline you credit your miles to does not appear to matter so much.