How can justice be achieved between the families of wives and their relatives if the husband faces problems with his wives due to their demands for equality in giving to their families and relatives?

It is not obligatory to be just between wives in honoring their families. Rather, the obligatory justice between them is in maintenance, clothing, housing, and lodging.

As for additional gifts, justice is not required in them according to most scholars. The Shafi'is and Hanbalis, and it is the more apparent view among the Malikis, hold that there is no harm for the husband to be generous to whomever he wishes among them after giving each one her obligatory right.

It is preferable to equalize between wives in gifts to avoid the differing opinion of those who made it obligatory. The Hanafis hold that equalization in maintenance is obligatory according to the view of those who consider maintenance to be estimated according to the circumstances of the spouses.