In sympa 5.0 and above, there is an admin table. You can use this to create a mailing list of all the list owners. Put this in the list config:
include_sql_query
db_name sympa
db_type mysql
user XXXXX
name sympa-owners
sql_query select distinct user_admin from admin_table where (role_admin = 'owner')
host localhost
Perhaps this could be accomplished using a list family?
