Family Sharing Plan
Unfortunately, we are not able to participate in the subscription linking due to not having access to Apple's billing portal. The gold membership, however, can be shared between children. Here's how:
1- All accounts (Parent and Kids) must have the same Primary email address listed in order to connect with each other. That's how our system recognizes the Parent-Kid connection. This also lists the connected Adult account as the Primary Guardian which allows for gold and Kid account management capabilities.
2- After all the accounts are connected, the gold must be purchased from within that particular connected Parent account. If the gold was purchased from a Kid account you will need to cancel that gold and then repurchase from within your Adult account.
For specific instructions on how to do this, please see this other FAQ: Can I switch Gold Membership between my Kids?