石叻侯

Here is a 1866 cover which has a special mark: "Forwarded By" "Trazar CO." "SHANGHAI". The cover was ...
假师爷 发表于 2014-11-14 14:13

Robert, what 老由said is true. You could easily find this type of private Forwarded mail under China Treaty Port selections.  
Interasia auction normally will cater a section for this.  You can browse through their past auctions for reference.