There is provided arrangements for controlling and supporting network sharing. A set of common system information which applies to communication networks sharing at least one shared local communication area for communicating with host network elements is prepared. A set of dedicated system information which applies to at least one of the communication networks sharing the at least one shared local communication area is prepared. The dedicated system information is addressed only to host network elements being configured to support sharing of a local communication area. System information including the set of common system information and the set of dedicated system information is transmitted. The common system information includes an information element indicating radio frequency channels used by neighboring local communication areas of the communication networks that share the at least one shared local communication area, said neighboring local communication areas neighboring the at least one shared local communication area.