A method for implementing a SIP feature includes, in particular embodiments, establishing a communication session via a communications platform between a first and second user and receiving a request from a third user to join the communication session. The second and third users are from a plurality of users using a shared line. The method further includes integrating communications of the third user into the communication session. In particular embodiments the method includes establishing a communication session between a first and second user via a communications platform. The method also includes receiving a select request that locks the communication session so that a third user cannot resume the communication session with the first user. In particular embodiments the method includes receiving a request from a first user of a shared line to enable a privacy feature that reduces call information generated by the communications platform in remote state notifications.