Until what relationship in the family should help for a person in need be counted as Zakât?

Support to minor children, wife and -if necessary - parents is obligatory, but support for others is facultative. Zakât as support for persons in need can be given on a personal level (which is quite common in non-Muslim countries). How are the rulings for giving to (more or less) far relatives of oneself or of the wife? Side question: Are the rulings for a woman the same? ---------- Concrete example: I pay (stately) school fees for the children of sisters of my wife in Kenya and a cousin of myself in Somaliland. The parents cannot afford this. Should I count this as Zakât?