Does establishing a cooperative society for members of a single tribe, to assist them in permissible matters without harming others, constitute fostering the prohibited spirit of tribalism?

Every gathering that establishes allegiance and disavowal based on something other than the banner of Islam is forbidden. A Muslim's affiliation with their country, people, or race is blameworthy if it is for mutual support and solidarity, not based on right and wrong, but solely on nationalism or ethnicity. However, affiliation for the purpose of acquaintance and cooperation, not pride and contention, is permissible. If the purpose of establishing a tribal association is cooperation and mutual support in permissible matters, then there is no harm in it; rather, it is commendable, with the necessity of guidance and advice to ensure it does not deviate from the legitimate framework.