Hi Rajesh,
I have manually updated "X" flag in NOT_RELEVANT in an existing event to check whether it is visible in EH_LIST.
The event message is not still visible in EH_LIST. So, if you think this is good then you can go ahead with this approach. I couldn't see any issue unless until if run any report and check this flag specifically to ignore or include.
Edited[Gopi]
Regards
GGOPII