iCloud Family sharing

So I am wanting to have my husband’s and my account both on family sharing where when we back up our phones they both back up in the family sharing and not having to buy extra storage for both phones. I can share with him but right now all of his back ups only go to his iCloud account so we are still having to pay for two separate iCloud upgrades. Is there a way for both of our phones to back up to the family sharing so that one of us doesn’t have to buy the extra storage?