A member of a Virtual Concatenation Group (VCG) can be temporarily disabled under control of a Link Capacity Adjustment Scheme (LCAS). The VCG comprises a number of link members, in which payload data are transmitted. A management command (MLOCKOUT) is transmitted from a management system to at least one of the source and sink side for one member requesting the member to be temporarily disabled. In response to the management command a forward control message is transmitted from the source side comprising a message (FDNU) indicating that payload data of the member shall not be used, and transmission of payload data for the member is discontinued. In this way temporary disabling of a VCG member is provided, in which it is ensured that the same member is enabled again when the operation requiring the disabling is completed, and which can be handled as a separate function by the management system.