This is just a sketch, mind you,....
1. establish a point of receipt and a process for receipt. This might be the same as what you do today for receipt of subpoenas. In our institution, they go straight to a dedicated fax in our compliance department.
2. establish and maintain a log of service. You will be served everyday until the attachment is satisfied or vacated. Yours is not the only bank being served, so this takes less time than you'd think.
3. establish an account for holding seized funds.
4. Interdict wire transfer or other funds transfers and seize funds where the entity is found. In our institution, we simply created a custom list in our sanction scanning software.
5. document and report.
6. track staff time devoted to the activity. Your bank isn't getting paid for the attachments, but you *will* pay for ignoring them.