[NTG-context] Citation of two books with extra information

Hi all, is it possible to cite two books and include page information for each of them. To give an example I'm looking for something like \cite[extras={, p. 123}, extras={, p. 456}][BookOne:2000, BookTwo:1900] which should be processed as (BookOne Authors, 2000, p. 123 and BookTwo Authors, 1900, p. 456) This does not work because the first "extras" is overridden with the second. It's possible to append Information to the second citation but not to the first or to both. Any suggestions how I might achieve this? Thanks! Steffen