Currently I can assign application for open some files based only on mime type. But, for example, I have file disk1.k3b --- this is K3B project file also this is zip arhive, Thunar recognize it as ZIP file and open it in assigned program, but I want open ZIP files in Arhiver manager and .k3b file in K3B.
Thunar uses the shared mime database. You can add a new mime type with the glob pattern *.k3b for k3b files. See the documentation for the shared mime database (-> freedesktop.org).
If you want a GUI to add to/edit the MIME database, you can use the ROX MIME-Editor at http://rox.sourceforge.net/desktop/MIME-Editor :) You can eventually install it using Zero Install: http://www.zero-install.org/ It's integrated with the Xfce >= 4.3 panel: http://rox.sourceforge.net/desktop/node/269
Resolving to INVALID then.