No, this is not possible.
But I have written for you an UltraEdit macro which maybe creates the result you want. It's an extended variant of the macro described at
How do I remove duplicate lines?.
You must have the 2 files opened in UltraEdit. First it copies to content of the current file and pastes it at top of the previous file and inserts a line with » as marker to divide the 2 contents of the files.
Then all trailing spaces and blank lines are removed and the last line is also terminated with a CRLF if the line termination is missing at the last line. Next all lines are marked at start of the line with a special marker string. See the linked thread why.
The following first main loop deletes all lines which are 100% identical.
The second main loop deletes all unique lines from first file and marks all lines where the string of column 1-6 is identical (but not the rest).
Next all lines with unmodified start of line marker string are deleted because they are unique in the second file.
Last all the markers are removed and the file is sorted. The result is a file which contains only the lines where column 1-6 are identical but not the rest. The last command opens the Save As dialog to store the results file with a different name to avoid destroying the content of the current file.
I could rewrite the macro to produce a different result format if you want it not in this simplified format.
Enable the macro property
Continue if a Find with Replace not found for this macro. The macro is written for ASCII DOS files and not Unicode/UTF-8 files or files with UNIX/MAC line endings without permanent or temporary conversion to DOS!
InsertMode
ColumnModeOff
HexOff
UnixReOff
Clipboard 9
SelectAll
Copy
EndSelect
Top
PreviousWindow
Top
Paste
IfColNumGt 1
"
"»
"
Else
"»
"
EndIf
TrimTrailingSpaces
Loop
Find "^p^p"
Replace All "^p"
IfNotFound
ExitLoop
EndIf
EndLoop
Bottom
IfColNum 1
Else
"
"
EndIf
Top
Find RegExp "%^([~^p]^)"
Replace All "#MOFI_RULES#^1"
Find "#MOFI_RULES#»"
Replace "»"
Top
Loop
IfCharIs "»"
ExitLoop
EndIf
StartSelect
Key END
Cut
EndSelect
Find MatchCase "^c^p"
Replace All ""
IfNotFound
Paste
Key HOME
Key DOWN ARROW
Else
Key DEL
EndIf
EndLoop
Top
Loop
IfCharIs "»"
ExitLoop
EndIf
Find RegExp "#MOFI_RULES#??????"
Copy
EndSelect
Key LEFT ARROW
Find MatchCase "^c"
IfFound
EndSelect
Key HOME
">"
Find MatchCase Up "^c"
Replace ">^c"
Key HOME
Key DOWN ARROW
Else
DeleteLine
EndIf
EndLoop
ClearClipboard
Top
Find RegExp "%#MOFI_RULES#*^p"
Replace All ""
Find RegExp "%>#MOFI_RULES#"
Replace All ""
Clipboard 0
Find "»^p"
Replace ""
Top
SortAsc 1 -1 0 0 0 0 0 0
SaveAs ""
Note: The macro switches to the UltraEdit style regular expression engine. If you prefer a different engine, add the command UnixReOn or PerlReOn at bottom of the macro.