If a person hears Kaddish or Kedusha while reciting a Beracha Me’en Shalosh – meaning, while reciting "Al Ha’mihya," "Al Ha’etz" or "Al Ha’gefen" – should he interrupt his recitation to answer to the Kaddish or Kedusha?
Hacham Ben Sion Abba Shaul (Israel, 1923-1998) addresses this question in his work Or Le’sion, and he writes, based on the ruling of the Ma’amar Mordechai, that one should, in fact, interrupt to answer to Kaddish or Kedusha in this case (listen to audio recording for precise citation). As Hacham Ben Sion notes, this is in contrast to the ruling of the Tehila Le’David, who maintained that one may not interrupt his recitation of a Beracha Me’en Shalosh even to answer to Kaddish or Kedusha. The Tehila Le’David claimed that the laws of Hefsek (interruptions) that apply to Birkat Ha’mazon apply as well to the recitation of a Beracha Me’en Shalosh. And therefore, just as one should not interrupt Birkat Ha’mazon to answer to Kaddish or Kedusha, similarly, one should not interrupt a Me’en Shalosh for this purpose. The Tehila Le’David draws proof to his claim from the Shulhan Aruch’s ruling that a Beracha Me’en Shalosh must be recited while seated, just like Birkat Ha’mazon, thus indicating that Me’en Shalosh is subject to the same Halachot as Birkat Ha’mazon. Hacham Ben Sion, however, dismisses this proof, noting that the Shulhan Aruch’s ruling does not necessarily indicate complete parity between the laws of Birkat Ha’mazon and those that apply to Me’en Shalosh. The fact that they both must be recited in a sitting position does not prove that they share the same Halachot concerning Hefsek. Therefore, even though one should not interrupt Birkat Ha’mazon to answer to Kaddish or Kedusha, one should interrupt a Beracha Me’en Shalosh for this purpose.
This is, indeed, the Halacha.
Summary: If a person hears Kaddish or Kedusha while reciting a Beracha Me’en Shalosh – meaning, while reciting "Al Ha’mihya," "Al Ha’etz" or "Al Ha’gefen" – he should interrupt his recitation to answer to the Kaddish or Kedusha. During Birkat Ha’mazon, however, one should not interrupt to answer to Kaddish or Kedusha.
