I think there may be such a sequence for solving this problem:
- within the KiXtart logon script You must generate some .reg file, which will write the logon user name directly into the registry key "HKEY_LOCAL_MACHINE\Network\Logon\username" (Win9xx) at the time of comp startup (f.e. "REGEDIT logon.reg" from autoexec.bat);
- while generating this .reg file within the KiXtart logon script You must check, if current logon username is one of Your's admin names. If so, then skip generating new .reg file and leave the old one with someone's logon name, who logged before.

Seems to me this will be a reliable solution...

PS: Sorry for my English. My native language is Kix32 logon script processor ;-)