In an embodiment, a client device associated with a first user performing a registration procedure with an Internet Protocol (IP) Multimedia Subsystem (IMS) network to register the client device to a first user for IMS service. The client device communicates (e.g., via GRUUs) with one or more other client devices that are also registered to the first user for the IMS service to obtain rich communication suite (RCS) capability information for the one or more other client devices. The client device receives a request (e.g., a SIP OPTIONS message) to report the client device's RCS capability information, and then transmits, in response to the received request, a message (e.g., a SIP 200 OK message) that indicates both (i) the client device's RCS capability information and (ii) the RCS capability information for the one or more other client devices.