This is what I have tried but this won't handle multiple levels. Is this the recursion rabbit hole?

DECLARE @GroupCode varchar(20)

SET @GroupCode = 'A'

SELECT DISTINCT

Member

FROM

(

SELECT

Member

FROM Groups G

INNER JOIN GroupMembers GM

ON G.GroupCode = GM.GroupCode

WHERE

MemberType = 'Individual' AND

G.GroupCode = @GroupCode

UNION

SELECT

Member

FROM GroupMembers

WHERE

GroupCode IN

(

SELECT

Member

FROM GroupMembers

WHERE

MemberType = 'Group' AND

GroupCode = @GroupCode

)

) dataset