German to English Tech/Engineering Construction / Civil Engineering Electrical Engineering/Contract

"Abstimmungen mit ausführenden Firmen von Fremdgewerken müssen vom Auftragnehmer eigenverantwortlich durchgeführt werden."

From a tender document for electrical work, I think I understand as much as that the "gewerke" refers both to the "trade" carrying out the work (later context uses the word in this way), as well as to the systems themselves. The dual-use and the "fremd" are throwing me off, though. Is there an equivalent word in English? Any help appreciated! Thanks!