Is it permissible for three people (a father and his two sons) to share a quarter of a cow as an Udhiyah (sacrifice), and would that suffice them?

It is not permissible for three or two individuals to share a quarter of an Udhiyah cow unless they are united in their expenses. In that case, a quarter or any other part suffices for them, provided it is not less than a seventh of the cow. However, if they are separate in their expenses, each one must independently own a seventh.