4. The seven blessings are recited only when the follwoing conditions are met:
a.There must be ten adult males present (the hatan is considered one of them).
b.The meal has to take place in the residence of the bride and groom (bet hatanim).
c. There must be at least two new guest (panim hadashot), who did not participate in the wedding and previous sheba’ berakhot.
When one of these conditions is not met, then if at least three adult male are partaking of the formal meal, they recite just the last berakha, asher bara
In some Sephardic communities in the diaspora the sheba berakhot are recited, whether the meal is taking place in the house of the groom or in a different place (consult your local rabbi). The other two conditions, panim hadashot and minyan, are identical for every Sephardic community.
The Ashkenazi custom also allows reciting the sheba berakhot even if the meal does not take place in the residence of the new couple, and even if just one new guest, not two, is present at the occasion (Rabbi Knohl).
5. When the Sheba Berakhot are recited, the custom is to have two cups of wine: with the first cup, one says Birkat haMazon and at the end of the Sheba Berakhot, he himself says “bore peri hagefen”. With the second cup, they say the other six berakhot. Once the last berakha is recited, the wine of the two cups is mixed and given to the bride and the groom. When only the berakha Asher Bara is recited, the custom is to say first bore peri hagefen and then asher bara.