Inline lists are usually conditional normally as they are related in some way to one of the detail columns in the row that you are viewing in its detail view. Why don’t you phrase the question in a way that explains what you want to do at a little higher level. For example:
I want to show a list of all people who have signed up for a trip.
Actually take a look at this post from earlier today. Think of the Events as your Trips. I used Participants as the name of the list of people and Attendees for the names and events link.