Messing up /etc/group

["J.C. Roberts" <unknown_(_at_)_abac_(_dot_)_com>]

I realize you can and probably should use "usermod -G" to add a user
to a group but I was wondering if doing it by hand using vi on
/etc/group will screw anything up?

I'd like to do simple edits to the group file like the one mentioned
in afterboot(8)
change
	wheel:*:0:root 
to
	wheel:*:0:root,myself
I wanted to make sure it's OK to do this through vi or if there's
something like vipw or visudo for the group file?

Best Regards,
JCR