I saw that we got a spam on the group address. Since the group is
public, anybody can send spams... The inconvenient is that the emails
from outside the group appear in the discussions list, together with
group members' posts. I tested that using a yahoo email address, that
is not registered to the group; I sent an email with title "this is a
spam", and it appeared in the discussions list.
Fortunately, it is possible to remove these spams from discussions; I
removed both spam messages.
Happy Christmas and New Year
Horatiu