Told to be part of the family (7)
I believe the answer is:
related
'told' is the definition.
(as in relating a story)
'be part of the family' is the wordplay.
'be' becomes 'relate' (relating is a kind of being).
'part of the family' becomes 'd' (I can't explain this - if you can you should give a lot more credence to this answer).
'relate'+'d'='RELATED'
'to' is the link.
Can you help me to learn more?
(Other definitions for related that I've seen before include "As siblings obviously are" , "Told in detail, being connected" , "Connected by blood or marriage" , "Recounted" , "Connected, by kinship say" .)