Editfiles logic question

[Chip Seraphine]

Question for you zen masters of editfiles out there....

I am interested in finding out if any lines of my vfstab file contain 
the word "ufs" but do NOT contain the word "logging"; if so, I will 
define the class "FileHasUnloggedLines".

I am hampered by the lack of a BeginGroupIfMatch to go with the 
BeginGroupIfNoMatch (or at least a groupelse type thingie) and the 
inability to undefine classes.

        ForEachLineIn "/tmp/vfstab"
                #Ignore if the line contains "logging"
                BeginGroupIfNoMatch "^.*\blogging\b.*$"
                        #Ignore if we have "ufs" in the line
                        BeginGroupIfNoMatch "^.*\bufs\b.*$"
                                DefineInGroup "no_ufs_in_line"
                        EndGroup

                        BeginGroupIfNotDefined "no_ufs_in_line"
                                DefineInGroup "FileHasUnloggedLines"
                                #undefine no_ufs_in_line here
                        EndGroup
                EndGroup
        EndLoop


The above does not work because once no_ufs_in_line is set, it stays 
set; a subsequent line cannot unset it, so the bottom group will never 
fire if the first line seen contains "logging" and/or does not contain 
"ufs".

Is there an easier way to do this within the editfiles syntax?  Or am I 
completely barking up the wrong tree?

It would be easy enough to just schedule a periodic RunScript that has a 
perl or python script scan for the appropriate lines, but I am hoping to 
do this convergently (i.e. within cfengine).