Pursuant to sections 517 and 613 of the Retirement and Social Security Law, the system shall establish a special fund, to be known as the Tier 3 through 6 Member Contributions Fund, to account for the contributions deducted from members' wages. All moneys withheld from such members' wages shall be recorded in individual accounts within such fund, and all withdrawals and refunds of such contributions shall be deducted from the accounts in such fund.