Md. Code, Commercial Law § 15–603

(a) While the attachment remains a lien, the employer/garnishee shall withhold all attachable wages payable to the judgment debtor and remit the amount withheld to the judgment creditor or his legal representative within 15 days after the close of the last pay period in each month.

(b) If the employer/garnishee is served with more than one attachment against the same judgment debtor, then the attachments shall be satisfied in the order in which they were served, and each prior attachment must be satisfied before any effect can be given to a subsequent attachment.