tunnel for one pppoe user

I have routed network (ospf) and on every node (mikrotik) i have pppoe server for clients on that node. Node_1 have gateway_1 and other nodes (Node_2,Node_3 …etc) have gateway_2. I need one client on node_3 to redirect his traffic to node_1 so he have gateway_1. How can i do this? I know that i can do this using mangle and packet marks but then i have to create marks on every node that is between client and gateway. Can i do this on some easy way like tunnel? Here is picture of my network.
mts.jpg

EOIP tunnel becan be the way…