The present disclosure concerns cable-covering tube assembly for a roller blind actuation cable, comprising a first cable-covering tube defining a cable-receiving cavity; and at least one tube connector extending at least partially in the cable-receiving cavity and comprising a cable-mounting portion couplable to the free end portion of the roller blind actuation cable; and a coupling portion couplable to the coupling portion of a similar tube connector. It also concerns a cable-covering tube system and a roller blind actuation assembly comprising first and second roller blind-operating systems having each a driving assembly and a unidirectional angular coupler, and a biasing member operatively coupling the driving assemblies and extending between their respective unidirectional angular couplers.