“Prescription Broker” sounds like a black market agent that buys prescriptions cheap from old ladies and sell them dear to drug addicts. I very much prefer the Danish translation (see ref. 2) which focus more on "oppbevaring" than on "formidling".

The role of the Reseptformidler is to store the prescription until the patient asks for it to be dispensed at a pharmacy. This ensures that the patient retains free choice of pharmacy, even in the case of repeatable prescriptions. The Reseptformidler only stores a prescription long enough to support its being dispensed; it is deleted after the prescribed quantity has been dispensed, or after it has expired, which ever comes first. A doctor can also recall her/his own prescriptions through functionality in the EPR.
http://www.helsedirektoratet.no/selectedtopics/electronic_pr...

Prescription Repository: Every medical prescription in the primary sector in Denmark is processed by this system(200,000 prescriptions daily)
http://www.trifork.com/default.asp?Action=Details&Item=23

Tror dette kan handle om et program. Det kan være dekning for å kalle en "formidler" for en "utveksler" fordi data kommer inn fra noen og går videre til andre.
Er derfor enig i det ene forslaget ditt.

Så fremt det ikke bare dreier seg om rene resepter, er vel "broker" mest brukt i datasammenheng, se ref.