From: Rabbi Moshe Sofer
To: Rabbi Ber
A hired melamed reciting Kaddish for a deceased woman who left no sons has no inherent right to share in Kaddish recitations or prayer leadership with actual mourners, because a hired stranger lacks both partnership standing and familial obligation. The Chasam Sofer rules that mourners' rights to lead prayers cannot be revoked by communal pressure, and suggests as a compromise that the hired person may join a mourner in a simultaneous third Kaddish following the Sephardic custom.
Source: Shu"t Chasam Sofer YD §345