Looking for suggestions (or a straight out can't be done) to solving the challange below.
We have 5,000 units that are required to be serviced. There are fifty sites to visit. Each site has a different number of units.
Spare units are required to be delivered to a site and staff have one week to swap units. A site will have more units than are spare (sixty being serviced, sixty being swapped, sixty on the road)
To reduce the impost of swapping units, thirty units will be dropped at two sites. Swaped units are picked up and returned to the depot for servicing. Serviced units are dropped off at the next two sites and the previous weeks swaped units are collected in the same run.
Week 1 Drop off Site 1 Site 2 Return to Depot Week 2 Pick up Site 1 Site 2 Drop Off Site 3 Site 4 (order does not matter) return to depot