Maryland Code, Criminal Procedure § 10-107

(a)(1) In this subtitle, if two or more charges, other than one for a minor traffic violation, arise from the same incident, transaction, or set of facts, they are considered to be a unit.

(2) A charge for a minor traffic violation that arises from the same incident, transaction, or set of facts as a charge in the unit is not a part of the unit.

(b)(1) If a person is not entitled to expungement of one charge or conviction in a unit, the person is not entitled to expungement of any other charge or conviction in the unit.

(2) The disposition of a charge for a minor traffic violation that arises from the same incident, transaction, or set of facts as a charge in the unit does not affect any right to expungement of a charge or conviction in the unit.