Cannot syncrhonize an linear array of nodes in syncro sleep mode with XBee 900HP 200k in DM

HI Everyone,
I have a linear topology (of four) where the first is a sleep coordinator and the following are set to synchronous sleep mode. As from the second, the coordinator cannot be reached, how can I synchronize the entire Xbees line including the distant end point to bring data from the last node and transport it by the network to the coordinator. All are 900HP Pro SB3 with DigiMesh firmware. So far I see the synchronization data between the coordinator and the first node, but not the rest. The configurations are as follows:
First coordinator, is a SM=7,SO=5,SN=1,SP=2EE0,ST=BB8,WH=0. The rest has SM=4 and SO=2. I suppouse the problem is in the SO=2 parĂ¡meter of the last but im not sure.
Thanks for the help