interpenetrate

(verb) penetrate mutually or be interlocked. Synonyms: permeate. Example: "The territories of two married people interpenetrate a lot."

(verb) spread or diffuse through. Synonyms: permeate, pervade, penetrate, diffuse, imbue, riddle. Examples: "An atmosphere of distrust has permeated this administration." "Music penetrated the entire building." "His campaign was riddled with accusations and personal attacks."