Process Corners set up problem

Basically I know how to set up a process corners for multiple model library, however some fab provide model files which include several

 different device sections in one file. For example, there is a model file "mos.scs" which include sections like "tt", "ss", "ff",  "tt_25",

 "ss_25", and "ff_25" for .13um and .25um devices, then I should define "mos.scs" twice in the process corner. After I save the set up,

I find the later define will overwrite the previous one. One solution is to have different files for different devices, but I do not want to change

the model files.

Is there another way to set up the process corners?

Thanks in advance if anyone could give some advice.