The following letter is interesting for us. Three different postal systems and double disinfection. It was written in Mostar (Bitola) on 7 October 1856. Sent with Ottoman post to Alksinac. Here it was disinfected and stamped with Kardosh type 1b cachet. The Serbian post (Alksinac one line Cyrillic cachet) took the letter to Semlin (Zemun). Here it was disinfected for the second time. The Austrian post carried it to Beograd and Pesth received 17 October. The receiver it was the company John it is looking for.
I will thank for a translation of the hand-writing scan in photo 2. Does anybody knows if A. Chrystodulo in Beograd was a forwarding agent?