Q. Can you make a Sholom Zochor for a newborn baby on Shabbos Chazon that is also Tisha Beav (nidche) as in this year.
A. Horav Shlomo Miller's Shlit'a opinion is that since this celebration is always done, omitting it on this Shabbos would be considered as avelus befarhesia and therefore it is permitted.
A similar case would be permitting a father on avelus to attend the sholom zochor of his newborn son at his home.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit'a