Hacham Ovadia Yosef ZT"L, in his work Chazon Ovadia (Laws of Purim, p. 181), writes that one must allocate some time for learning Torah on Purim, either before or during the Purim meal. People often become very involved in the Mitzvot of the holiday and as a result forget their obligation to spend some time studying Torah every day. It must therefore be emphasized that on Purim, as on all other days of the year, one must set aside a period of time for Torah learning.
In this context Chacham Ovadia tells the story related by Rabbi Menachem Mendel Morgenstern of Kotzk (Poland, 1787-1859) about the father of his son-in-law, Rabbi Avraham Borenstein of Sochatchov (the "Avnei Neizer," Poland, 1839-1910). One year, during the Purim festivities, Rabbi Avraham's father moved away from the celebration and began studying Torah. The Rabbi of Kotzk remarked that at that moment, Rabbi Avraham's father was the only person in the world engaged in Torah learning, as everybody else was preoccupied with the Purim celebrations. It was therefore he who sustained the world during those moments, and for this was rewarded with a son who would become one of the leading Torah sages of his generation.
If a person completes a Masechet (Talmudic tractate) on Purim, may he combine the Siyum (celebration of completing a tractate) with the Purim meal? A fundamental Halachic principle forbids merging Mitzvot together rather than paying individual attention to each ("Ein Osin Mitzvot Chavilot Chavilot"). Should we apply this rule to forbid making a Siyum at the Purim meal, as one thereby combines two Mitzvot into a single context?
Hacham Ovadia rules (Chazon Ovadia – Laws of Purim, p. 185) that one may combine the Siyum celebration with the Purim meal because the two Mitzvot are performed through the single act of eating a meal. The rule of "Ein Osin Mitzvot Chavilot Chavilot" forbids performing two separate Mitzva acts like using a cup of wine for Birkat Hamazon and then Kiddush. It does not forbid fulfilling two Mitzvot through a single act. Thus, for example, the Talmud Yerushalmi allows one to drink wine produced from fruits of Shemita (fruits from the "sabbatical" year) to fulfill the obligation to drink four cups of wine on Pesach. Even though partaking of Shemita produce constitutes a Mitzva, and drinking this wine thus fulfills two Mitzvot simultaneously, this is nevertheless permissible because only a single Mitzva act is performed. Similarly, Kohanim may partake on Pesach of Matza baked from Teruma (the required gifts to the Kohen from one's agricultural produce). Here, too, through the single act of eating, the Kohen fulfills both the obligation of Matza and the Mitzva to partake of Teruma, and thus the rule of "Ein Osin Mitzvot Chavilot Chavilot" does not apply. Likewise, then, it is permissible to conduct a Siyum together with the Purim meal. (See also the Daily Halacha entitled "From The Concept of Havilot Havilot- Is it Permissible To Have One Sedua for 2 Siyumim")
Summary: One must make a point to allocate some time either before or during the Purim meal for studying Torah. A person who completes a Masechet of Talmud may conduct the Siyum together with the Purim meal.
