There is a quick search in the list of post services (by name and SID). The filter input field is next to the list of services: in the track properties window, in the group properties window, in the settings window, etc.
Enter part of the service name ("FromGonduras" for example), and get a list filtered by the entered line.
To add a service that is not in the list, you should send one, or better - several tracks that should be tracked on the service and URL(link) to the tracking web site. The best way to do this is on the forum on our site, following the rules.