[Avodah] Zimun - 2 women with 1 man - permitted?

[Micha Berger]

On Sun, May 08, 2011 at 11:25:29AM +0300, Danny Schoemann wrote:
: The MB in 199:6:(12)...
: The Shaarie Teshuva (ibid) actually brings the Gan HaMelech (Siman 75)...

: Reading between the lines, it seems like technically it should/could
: be permitted, but the Minhag was to not do so.

But this presumes a mixed-gender zimun is a matter of reshus. I had asked,
in reply to the same post by RtSB that RDS is replying to, why this
would be. Given that men and women have an equal chiyuv in bentching,
why would the prohibition against breaking up a zimun apply any less
when some of the mechuyavim are actually mechuyavos?

Clearly, given the minhag, this is the case. What I don't understand is
the reasoning.

Tir'u baTov!
-Micha

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Micha Berger             Today is the 19th day, which is
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