Under Rule 85 of the Rules of Court, joinder of parties is appropriate where: (1) separate actions would give rise to common questions of law or fact; and (2) the rights to relief arise out of the same transaction or series of transactions. Where an employment termination, settlement agreement involving property transfer, and subsequent eviction proceedings all arise from the same factual circumstances, joinder of the employer company, its managing director, and the Registrar of Deeds serves the interests of justice by avoiding multiplicity of actions, saving time and expense, and preventing a party from having to prove the same facts repeatedly in separate proceedings.