Supply lines (Fallout 4)

He built supply lines not on the settlers, but on the characters. I want to send settlers to this job, so that the characters would hang out at my base and not go anywhere. I read a lot of forums, everywhere they write that you also need to press Q in the construction mode and remove the lined supply line, i.e. do everything in reverse order, but I can not. Let's say he sent the Strong Man to the Greentop Greentop. I found Strongman, opened the construction menu, I press Q, but there is no Greentop Greenhouse in the list. I choose, for example, the Castle, the resource is assigned, I open the construction menu again, the Castle is not in the list. Let's say I go to the Castle to interrupt the appointment, I choose a local bum, I want to send him to my main base, from where I sent the Strongman, but now my main base is not on the list. What am I doing wrong? How can I make them hang out only at my base? Let the homeless work.