These could be mail for other addressees (Parco Tirreno, La Salle, etc.) frequently reach the PCF.
Mail for other Institutions: Put the mail into the tray for stray mail. When the postal service comes, give these mail to the mailman.
Mail for PCF Alumni: Put in the corresponding pigeonhole: in Rome, Italy outside Rome, Philippines. Contact and ask the addressee what to with the mail, or send the mail through somebody going to the addressee’s area.