Context : JW GROM (full name: Jednostka Wojskowa GROM im. Cichociemnych Spadochroniarzy Armii Krajowej, English: ``Military Unit GROM named in honour of the Silent Unseen of the Home Army'') is Poland's elite counter-terrorism unit. 
Subject : JW GROM 
Relation : military branch
What army did JW GROM serve in?