Learn Italian: I capisala organizzano il ricevimento. - The head waiters organize the reception.

Caposala is a compound noun made of capo (boss/head) and sala (room). When capo- means the 'head of' or 'boss of' something, only the word capo changes to plural (capi), while the second word stays singular. So, 'head of the room' becomes 'heads of the room': capisala.

Since sala is feminine, why does capisala use the masculine plural article i?

The gender of this compound noun is determined by the person (capo), not the room (sala). A male head waiter is il caposala, so multiple male (or mixed) head waiters take the masculine plural article: i capisala. If you meant a group of entirely female head waiters, you would use the feminine plural article, but the noun itself stays exactly the same: le capisala.

Does ricevimento only mean a party or banquet?

While it means a formal reception or banquet here, ricevimento comes from the verb ricevere (to receive). It can also refer to a hotel front desk, or a professor's office hours when they 'receive' students (orario di ricevimento).

I see organizzano has a double Z. Is this verb related to the English word 'organize'?