4 The Local Board is authorized, in relation to the powers granted to it by section 3 with respect to the marketing of hogs in interprovincial and export trade, to make orders fixing levies or charges and imposing them on and collecting them from persons described in section 3 who are engaged in the marketing of hogs and, for such purposes, classifying such persons into groups and fixing the levies or charges payable by the members of the different groups in different amounts; and the Local Board may use such levies or charges for its purposes, including the creation of reserves, the payment of expenses and losses resulting from the sale or disposal of hogs, and the equalization or adjustment among producers of hogs of moneys realized from the sale thereof during such period or periods of time as it may determine.