Here is how this is done:
Create the primary parent account and the child account and make sure to have the box checked to sync contact information with the primary parent.
Go to the second parent account in they system, and click the "Add Family" button.
A box will appear asking who should be added to the account. Since the child's account has already been created, you can click Search down below at the existing customer section to find the child or if you already know the Customer ID (CID) you can type it in the box. Click ADD once the CID is entered in the box. Repeat this process if there are more children to add.
Leave the box unchecked because you only want to sync the contact information with one parent.
Now if each parent logs into their online account they will see their children.
Important notes:
Only the primary (synced) parent will receive team e-mails or marketing e-mails geared towards the kid's season. You can add an "alternate email" to the primary account for the additional parent to receive these emails.
Adults can never see other adults info in their online account even if they are part of the same family in DASH. This is for privacy reasons and in the case of separated or divorced families, it is best not to allow ex-spouses access to any personal information.