Answer:
Since there are no limitations for placing holds on a certificate of deposit, take whatever operational steps are necessary to prohibit any early withdrawals from the certificate to protect the bank from potential loss.
Whether half or all of the funds were initially deposited into the certificate, if the check is returned unpaid the impact on the certificate is the same. Even with rates still near historic lows, as a consumer I would have been taking my check elsewhere if you tried to deprive me of a week's interest by forcing me to deposit all of the check into a checking account before allowing me to open the certificate.