As B*Cat points out, it sounds like it's probably just a CP (Carrier Pole) ??
However, if it is, it shouldn't carry the same markings as the DP for the obvious confusing reasons. If there is just the one additional CP route, then the subsequent CP's will be marked 1,2,3 etc etc .... depending on how many CP's make up the route.
If there are two or more different CP's routes, (usually in rural circumstances, feeding multiple farms etc), then the CP's will be marked 1a, 2a, 3a etc etc for one of the routes, then 1b, 2b, 3b etc etc .................. and so on and so forth.