I believe that at this moment, the only possibility to simulate a "looped" movement, is to draw a line that goes multiple times between the desired points.
Is there a possibility that a loop-functionality could be added to the program? For the 3D path I'm thinking of the possibility of an "open" path (A->B->C->B->A) and a closed path (A->B->C->A). An other nice feature would be to have multiple resources following the same path, with an interval between them.
Usage of the feature:
1) Multiple dump trucks moving between excavation and fill. Defining a closed loop, assigning one resource, defining how many instances of resources, interval between them, number of loops, assigned to one task.
2) Hoisting between delivery and processing site