A commander may appoint an officer to command of a subordinate or detached unit. If none is appointed upon marches, guards or in quarters different organizations of the National Guard of this State join in or do state duty together, the officer highest in rank of the line by commission there on duty or in quarters shall command the whole and give orders for what is needful in the service unless otherwise specially directed by the Governor, according to the nature of the case.
S.C. Code § 25-1-580