Is it possible, in particular cases, to make a Siyum Masechet of Mishnah instead of a Siyum of a Gemarah Masechet on the Fast of the first born, before Pesach? Thank you and Pesach Kasher ve Sameach

The Poskim differ as to whether a siyum of a masechet of mishna is sufficient for a seudat mitzva. HaRav Ovadia Yosef (Shu"t Yabia Omer I Orach Chayyim 26, 9-10; Shu"t Yechavve Daat I 40) cites the differing opinions and concludes that if someone or some study-group has completed a masechet of mishnayot, studying and understanding the mishna and the explanation of the Bartenura on the mishna, then that individual or study-group can make a siyum. It is not sufficient to make all those who attend the siyum- even if they didn't complete the masechet themselves- part of the seudat mitzva. I would add that if someone knows that there are first-borns who will not fast even if a siyum is not made, and the only possibility of a siyum is on a masechet of mishnayot, it is advisable to make i a siyum on a masechet of mishnayot (including the peirush) and to rely on those authorities who believe this is sufficient to make the seudah a seudat mitzva for all those attending. Chag kasher Vesameach!