LyX ⇒ Multiple Citations of one Source with one Entry in Footnote

[Crumble4all]

Hey guys!

I'm using Lyx for my bachelor's thesis and biblatex for the literature administration. All works fine so far, but I have still one major problem:

I want to cite one source several times on one page and then I want to still get only one entry in the footnote. For example, in the text it would say:

"Lyx is incredible comfortable [8], because it is very easy to handle [9]. Furthermore it is for free![10]"

Then, in the footnote I get:
[8] Lyx-Guide ....
[9] wikipedia.org ...
[10] Lyx-Guide ....

But I want it that way:

[8][10] Lyx-Guide ....
[9] wikipedia.org ...

How do I manage to do this?

Thank you!!