how this waveguide can be solved? modes of this waveguide?

this is cross-section of waveguide .the waveguide2 has outer most boundary of material type 0, while inner round object was of material type 1. same with waveguide3.

i have to solve them for modes for given frequency? on net i didnt find any analysis regarding these types of waveguides.
can any body help. any type of help.