To remove a contact that no longer meets your import strategy, but is linked to other school members on the same linked people record in Schoolcomms. You will need to completely remove the linked contact from the Childs record in Arbor.
When the import is next run they will be removed as a contact for this child from Schoolcomms.
You can then re-add the parent as a new contact in Arbor for this child if needed, do not link to any existing contact in Arbor if prompted.
Providing that they don't meet the import strategy they will not be pulled back across.
Alternatively if you only need to separate the linked contact records in Schoolcomms for each of the children that the parent is linked to.
You would need to remove the pupil (that you would like a separate linked people record for) completely from Arbor, then re-add as a new contact, do not link to any existing contact in Arbor if prompted. When you re-run the import the parent should then have separate linked people records for each of the children.
Wonde imports data from Arbor on an hourly basis so users will need to wait an hour after amending any details in Arbor before running an import to ensure the latest data is imported.