Sil,
As kellyz says, this place is a little off the trail, but trust the signs and they will get you there. There just aren't many of them, so doubts crept in, but we decided to trust the signs and found the place without trouble.
I'm sure I'm telling you something you already know, however.....The Finisterre option is getting quite popular, and with a party of that size booking ahead (if possible) would be prudent. We walked Le Puy to Finisterre last year, arriving in Finisterre mid-November. The only full albergues we encountered on the entire route were at Olveiroa and Corcubion. We loved this section, not to be missed. I believe there is now at least one additional albergue, I think it is in Vilaserio. We looked in at the school there, listed in the CSJ guide, and it looked OK but very basic. Perhaps it has been upgraded. I have also heard of an albergue named Casa Esperanza with 10 beds in Maronas, but nothing definite
Donovan