No state agency shall make expenditures of any federal Title XX monies, unless such expenditures are made pursuant to specific appropriations by the Legislature. In appropriating expenditures for social services as provided under Title XX, the Legislature shall specify the maximum amounts of funds to be expended by source of funds. To the extent not precluded by the terms and conditions under which financial aid is made available by the federal government, the Legislature may establish priorities for the activity being assisted and shall specify the major categories of services to be provided and the maximum amount to be expended in each category.