The tribological interaction between two rough surfaces comes down to the contact of microscale asperities, forming micro-contacts. Recent work demonstrated the existence of a critical asperity size d* governing a ductile-to-brittle transition for a given material in an adhesive wear situation. A single micro-contact of size d will plastically deform under shear if d < d*, or create a wear particle if d >= d*. Following a work done in 2D, an analytical theory for the interaction of multiple micro-contacts under tangential load is derived in 3D and compared to boundary element (BE) computations of rough surfaces. Three wear regimes are identified in both models: plastic deformations, formation of separated wear particles, and formation of combined wear particles encompassing multiple micro-contacts.