Your schedule that starts process A could end (stop decision within process) and the next task could be process B. If there is no work for process B (because it is ad-hoc) then it will just complete and the schedule will move onto the next task, otherwise it will do the work.
There is a roadmap item planned for the product for more intelligent Active Queues - where robots can manage their own work loads - hopefully we will get that in 2018.