How can I set Lumped port with GSS structure in HFSS

Hi,
I am a Newbie of HFSS
I am a Korean, and I am not good at writing English.
I want to know how to setting ports in GSS structure in HFSS
I explain this structure more specifically.
there are three pins like this |||
the first pin is a ground. the others are signal pins.
In simple GS structure, it is easy to set port. because the port take possession of part between Ground and Signal by using the lumped port method in HFSS.
However, in GSS structure in a row, if I use the same method above, the HFSS program says warning that Ports are overlapped.
How can I set ports like this structure?
please answer this problem. thanks

Please see attached HFSS file for basic Transmission Line setups using a Driven Terminal setup... It includes a GSSGSSG which should aid you in your needs. It is in HFSS14 and I have no access to other versions.

Have Fun

It is helpful! but my case is some different from it.
I attached my project file. please see it. It is like pogopin style.
I want to get S parameter matrix between G and S1 and between G and S2 and between S1 and S2.