The Attribute Editor for each of the emitters has its own texture emission attributes, so you can apply a different texture (or color) to each group of particles even though each emitter emits the same particle object.
With this technique, you can layer a single emitted particle object with various colors to create complex particle effects such as smoke or fire. The particles use the emitted particle object’s attributes except for color (and optionally opacity), regardless of which emitter emits them.
For example, suppose you add two surface emitters to a plane and connect a single particle object to the emitters. The plane can emit particles colored by a black and white checker texture at the same time as particles colored by a purple to yellow ramp texture. The particles are a single emitted particle object. You can display the emitted particles as any render type, for example, spheres, by setting the appropriate attribute in the Attribute Editor for the emitted particle object.