finding 3d printers in certain materials?

so currently on the internet there are a few sites where you can find local 3d printers, but i'm trying to print a model that is made up of parts of a few different materials, and I can't find anyone near me who can print them. Does anyone have problems finding different printers for all the different materials/parts of their models? How do you guys go about finding different printers for different materials/parts through the internet?