We do not mind if an external gang or player seeks for participation from here, the more players/events, the merrier. But do not just post a link to your website/forums, asking people to sign up over there. No advertising - its against the GTAForums Rules and Policies. Avoid posting external links and make proper use of your topic. You can post anything pertaining to your event within your topic - rules, schedules, results and what-not.
This also goes for referring members of this website to your PSN ID in order to apply and participate in events. All applications and any form of initial organisation should be tied to the topic itself and not through external means. This is an event that has minimal effort, and not enough to warrant its own topic. Look at other popular and successful topics to see what is generally expected. 6 bullet points is not sufficient.