I am not sure if it is the same throughout all of the hospitals in NJ, but I can speak from my experiences. In NJ, the ALS systems must be hospital based, but in my particular area of the state MONOC (a corporate EMS company with controlling input from like 13 hospitals) is its own company which operates completely separate from the hospital and in day to day operations has nothing to do with the hospital staff.
I worked as an ED Tech at Ocean Medical Center (Brick, NJ) (part of the Meridian Healthcare System) prior to getting my medic, and did part of my hospital based clinical paramedic training in the same ED under two different scopes of practice. At any of the hospitals under Meridian, to be qualified as an ED Tech you must have a BLS cert. You must either be an EMT-B, OR a CNA WITH 911 experience on a volunteer first aid squad as a non-EMT. ED Techs perform O2 administration, venous straight-stick phlebotomy, 12-lead EKG's (but know nothing about interpretation), fiberglass splinting/casting of non-displaced fractures and those already set by the MD, routine pt cleaning and pampering like a CNA, vitals, transport/physical transfer bed-to-bed of non-critical/non-tele patients to the floor alone, transport/physical bed-to-bed transfer of critical/telemetry patients to the floor with a supervising RN (in other words with all due respect, they walk and talk while you do the work), making/cleaning ED stretchers, stocking of supplies, and basic electronic charting of vitals and care provided to patients. You were not allowed to start IV's or give any medications unless you really consider O2 to be a medication.
As a paramedic intern in the ED, I could perform all of the duties of the paramedic under guidance of a supervising RN or MD, with the appropriate orders.
Under normal circumstances, the Paramedics are not stationed at the hospital but once in a while after transferring care of a patient, the nursing staff will request that the Paramedics attempt an IV on a hard stick patient because we are better at it. While the paramedics here aren't really supposed to provide any care within the confines of the hospital, because at Monoc they have no direct affiliation with the individual hospital (they aren't covered by the hospital for liability should something happen because they are not hospital employees, and have no privileges), they often do as a courtesy. Hope that helps some.