Here is the answer on how no mail status groups are handled:

"Al-Anon groups in “no mail” status are changed to “inactive” if the WSO does not receive a new address for the group after two years of being in “no mail” status. In the first quarter of every year, the WSO purges group records that have been inactive for at least three years and which do not contain any financial information. Inactive group records with financial information are retained for a period of seven years; this includes records with purchase orders, contributions, or subscriptions."