Many times I find myself davening in one Minyan while another is taking place within earshot. What is the proper way to handle such a situation (in terms of answering Amens, Kedusha, etc.)?
In a diffrent context dealing with the same problem.Reb Ovadiah Yosef says in places like the Western Wall or very large shul where multiple Minyanim are held simultaneously that one should respond to Kedusha and answer "Amen" to the Berachot he hears. Even though he had already recited Arbit, there is no Halacha forbidding answering "Amen" or responding to Kedusha of Minha.
I once asked a Rov regarding the Halacha of what to do in 770. There is one official Shacharis/Mincha/Maariv minyan ("the main minyan") and there are also side minyanim taking place under the Woman's section throughout the day. Between the "side" minyanim and the "main" Beis Medrash are mechitzos to avoid this issue
However, there are times when people (inappropriately) make their minyan in the "main" Beis Medrash.
My question to him was if I have to answer Amen/Barchu/Kdusha. He said that one really should if possible.