Not sure I understand the question fully, but I think I get the gist. And if I do, I asked a (somewhat) similar question recently.
My take is that your Concern of "longing for someone" can be shown throughout all four Sign Posts and yet when you get to the Sign Post of Innermost Desires, it can definitely explore the Concern of "longing for someone" through "experiencing rapture". Does that make sense?
In fact, I don't think you would have to stick with a gist of "longing for someone" through all 4 throughlines. That gist could change to reflect some other Innermost Desire while going through the Sign Post of Innermost Desire.