From: Rabbi Akiva Eiger
To: Obrzycko
Rabbi Akiva Eiger rules that an existing renter has priority over a co-owner seeking to rent an adjacent cellar. The co-owner's shared courtyard access does not grant him partner status — only that of a bar metzra — and all major authorities (Sma, Taz, and Maharshal, albeit for differing reasons) agree that a renter takes priority over a bar metzra, at least lechatchilah.
Source: Shu"t Rabbi Akiva Eiger §140