Sharing with other 1Password users

I've just made the move from a Family plan on Lastpass to 1P. This is after a divorce, and we're still untangling all our shared accounts.

I currently just have a personal 1P account. I've organized the remaining shared passwords that either the whole family needs to access (ie, Netflix, Hulu, etc) or that need to be shared just between me and my ex in vaults. 

If my ex gets her own 1P account, can I share a vault with her and have it show up in her 1P account? Or, does that require me to upgrade to the family plan and be the nice guy and let her have an account?