Is the voluntary affiliation of one tribe with another considered an act of disbelief (kufr), as mentioned in the hadiths?

Disowning and denying one's original lineage and claiming the lineage of another tribe is forbidden in Islamic law and is considered an act of ungratefulness (kufr نعمت) for Allah's blessing, as the Prophet (peace be upon him) said: "Do not forsake your fathers, for whoever forsakes his father has committed an act of disbelief (kufr)." However, affiliating oneself with another tribe through alliance and loyalty while retaining one's original lineage and not denying it is permissible.