If you have an autonumber primary key for the table you do something like this to count based on the Org_Name:
SELECT tblOrgs.PKID, tblOrgs.ORG_NAME, tblOrgs.PERS_NAME_LAST, DCount("*","tblOrgs","[ORG_NAME]='" & [ORG_NAME] & "' And [PKID]<" & [PKID])+1 AS BdMbrCount
FROM tblOrgs;
It will just...