“Love Recognizes No Barriers” - Maya Angelou 

Tosafos (quoted below) points out that a wall of a larger courtyard may be, in certain situations, a barrier for the establishment of a minyan, however in terms of answering amen, Kedusha, Barechu or being yotze Megillah or Shofar we follow the ruling from the Gemara Pesachim 85b:

Rabbi Yehoshua ben Levi said: Even a barrier of iron does not separate between the Jewish people and their Father in Heaven. Barriers are irrelevant with regard to prayer.

דְּאָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי אֲפִילּוּ מְחִיצָה שֶׁל בַּרְזֶל אֵינָהּ מַפְסֶקֶת בֵּין יִשְׂרָאֵל לַאֲבִיהֶם שֶׁבַּשָּׁמַיִם

This beautiful phrase is particularly apt during this time. Some are not able to participate in public prayer due to the pandemic and it is important to keep in mind, “Even a barrier of iron does not separate between the Jewish people and their Father in Heaven”.