poszczególnymi
The Polish word "poszczególnymi" is the instrumental plural form of the adjective "poszczególny." This adjective translates to "individual," "separate," "particular," or "respective" in English. As an instrumental plural form, it typically describes the manner in which an action is performed or the means by which something is done, and it refers to multiple distinct items or entities.
For example, in a sentence like "Zajął się poszczególnymi problemami" (He dealt with the individual problems),