Several things....
1) Tasks within a workshop are (r)epeatable. When the task is complete, it will be moved to the bottom of that workshops que even before the next task from the manager can be qued.
2) I don't want to exclude a workshop from the manager, I want to define what sublist of tasks that workshop will accept from the manager.
If I tell the manager to make 300 bone crafts, 100 totems, 200 wood crafts, and 300 stone crafts, the workshop dedicated to my bone carver gets only bone and totem orders, the stone crafter's shop gets only stone orders, and the undedicated ones get whatever the que shows as needing to be done next.
I can't just load up the bonecarvers shop with (r)epeated "make bone crafts" and "make totem"s, because if s/he runs out of bones, they will cancel the task.
And yes, I've had the animal trainer cancel a dog training task because all of my untrained dogs were still puppies. If you haven't, I envy your luck.
BTW, (r)epeating a "tame mountain goat" task ends up with the animal trainer attempting to tame the same goat over and over, instead of moving on to the next untamed one. Strange that.
(I use repeat to deal with "I want roughly the same number of wooden barrels, bins and beds made, but only half that number of buckets" alot. There end up being 7 tasks with the repeat indicator in the workshops task list, and still three slots for stuff from the manager. I did once forget to check in for a few years, and ended up with some 400 beds, but hey, whatever.)
Also, (r)epeated items do not count towards manager orders. The workshop won't stop putting "make wooden bucket" at the bottom of it's list simply because you only asked your manager for 30 of them. Your manager will still want 30 made, and the repeated task will keep repeating until you don't have any materials left or until there is no one to make them... or, you know, you take it off.