Legal Question in Real Estate Law in California

If the entire interest in the property is to be sold, all five grantees would have to sign. Otherwise, the new grantee would only take as to the interest as to the signing grantees.

The previous answer is pretty much right. If, however, the five grantees held title as joint tenants, and one or more of them has died, their interest(s) would have passed to the survivors by operation of law, and only the surviving owners would need to sign.

Also, a deed may be signed by an authorized agent as well as by the owner/seller in person, provided the agent has been authorized in writing. See Civil Code section 1091.