Merge two wsdl into one

Hi guys,

I heard that it is possible to merge two WSDL files into one. However, I don't know how to do it. I will probably want to do it manually, but whatever solution works is welcome.

Also, a link to good documentation would be appreciated OR/AND explanations of the basis to make this happen. 

#1- GenericService.wsdl
#2- MessageService.wsdl

INTO:

#3- MyMainService.wsdl

Thanks before hands 😉.