calibre does I believe use some url scheme internally, but it isn't exported to the OS. At least in theory that feature could be added; I don't know how much interest Kovid Goyal has in doing so, I guess we will see when he responds.
I don't know that it's possible (currently) to open at a specified location. For one thing, ebooks have no page numbers, so what reference scheme do you use instead?
P.S. The Development subforum is not meant for feature requests or asking how to use features -- it is for discussion about how to code for calibre, e.g. someone wants to implement a feature.