In GNU Midnight Commander, when you right click on a file and select Properties, then click on the Permissions tab, the Group listing is incorrect. It always gives the Group the same as the User. To see the correct group ownership, use the (ls -l)command in a terminal window, or set up a custom view in GMC that includes the group.
I was not able to replicate this problem with gmc-4.5.30-12 as shipped with Red Hat 6.0.
Would you mind trying the following just to be sure we are on the same page? Make a new file. Right click on it and select Properties, then the Permissions tab. The goup and user should be the same, if using the standard Red Hat User-Private Groups. In the Group drop down box, change the group to something else and click OK. Right click on the file again and go to the Permissions tab. What does the group say? On my system it reverts to the same name as the User, even though the group has actually been changed to something else (as can be verified with ls -l). Thanks for your help.
P.S. when I select About from the Help menu it says GMC 4.5.30. Where do you find the -12 in your 4.5.30-12?
Typing "rpm -q gmc" will display the name-version-release (the package release is -12)