Do you mean 3-way switches? In other words, one light is controlled by two switches? If so, any INSTEON switches will work. See the Multi-way Switch article on the wiki for details.
Does anyone make an insteon or indigo compatible 3 gang switch? I want to control my front porch and foyer lights but it's 3 switches.
You'd just put 3 separate insteon switches or dimmers in your existing 3 gang box. Be sure to derate the switches per the instructions and not overload them.