How do you get a Hired Hand to pick up a specific item?

In this other question, I asked how best to use Hired Hands. Apparently, their best use is to carry things (with a side order of "they set off arrow traps" and "fortunately, they don't live long"). So: how do you force your Hired Hand to pick up the item you want, rather than the rock that they decided to carry instead?

(Bonus question: if you're trying to get them to carry the Eggplant, how can you prevent them from splatting it on the landscape? Is it even possible?)