I am using biblatex+biber for the bibliography of my thesis. I use the numeric-comp citation style. Overall this works perfectly.
I generally use \cite to cite references; but occassionally also \cites, namely when I want to cite references in a specific (non-numeric) order, or when I want to specify page numbers for some (but not all) cited references using postnotes (i.e. between []).
My question is about the latter usage of \cites, for example:
\cites[pp.173--199]{SomeBook}{SomePaper} Which produces (10=SomeBook; 20=SomePaper):
[10, pp.173–199, 20]
I find the commas slightly confusing here. Therefore I was wondering if it is possible to somehow tell biblatex to use another separator, say a semicolon. So that I would get:
[10, pp.173–199; 20]
However, I do not want to replace commas with semicolons everywhere, only in this specific case. So all uses of \cite, and uses of \cites without postnotes, should still use commas.
If necessary I would be ok with a solution based on a separate command for the specific case. For example a \semicites command that uses a differently configured \cites internally.
EDIT 2 I changed my mind and went with a solution based on Marco's answer.