i think this is saying that with family account, i cannot share some things with just one person if several are on account? sorry, confused
In a Families account, you can certainly share items with just one person, no matter how many users are actually in the account. To do this, you would create a special vault just for you and this other person:
but wout that other person be able to later on share that vault with another family member?
You can choose whether or not a given family member can manage a vault.
Log into your 1Password account at start.1password.com (or your personalized login URL).
Click on Vaults in the sidebar to the right.
Select the vault in question.
From here you can manage who has access to that vault, and what level of access they have. When you add a family member to that vault, you can select the gear that appears next to their name and DESELECT the "Allow Managing" permission, while leaving Viewing and Editing settings as desired.
With Allow Managing disabled, that family member cannot modify permissions such as sharing this vault with another family member.
(This can alternatively be done from the People management screen in the web interface)
Indeed, as scottisloud explained, you can configure the vault both ways, depending on whether you want them to be able to share the vault or not