In IEEE 802.17 draft standard, bridging technique is suggested to connect multiple resilient packet rings (RPRs). However, we demonstrate that bridging technology may not be a feasible solution because too much of resources and overhead would be occupied or needed to transmit packets across multiple RPR sub-networks. To construct interconnected RPRs and thus solve bridging related issues, this paper introduces a new kind of RPR nodes, namely, RPR-X nodes, to interconnect multiple RPR sub-networks. In our solutions, standard RPR frame defined by IEEE 802.17 is used to transmit packets on the local RPR sub-network, the extended RPR frame (i.e., cross frame) is used to transmit the packets across different RPR sub-networks. For RPR-X node, it can identify and process both standard RPR frame and extended RPR frame. While for RPR-S node (standard RPR node), it can only identify and process standard RPR frame. Based on the extended definitions of standard RPR frame, we give a detailed design of MAC layer reference model of RPR-X node, and propose an original packet cross forwarding algorithm, with a view to transmitting the packets across multiple RPR sub-networks, and at the same time to guaranteeing the cross forwarding algorithm to be compatible with the standard forwarding procedure of RPR-S node. Theoretical analysis and simulation results demonstrate that the proposed methods perform well in terms of performance metrics such as network's throughput and end-to-end delay.