There is no such RP section.
So, given that right now everyone seems to be circling around actually starting an RP site up, let's start throwing around ideas for a backstory.
Here's a rough idea to get everyone started.
An expedition from Earth has been sent to check out a new planet that shows signs of habitability, consisting of Weyland-Yutani scientific vessels, civilian volunteer carriers, and a colonial marine ship. The planet was designated PL-129. The expedition's ships take up geostationary orbit around the planet once they arrive and start ferrying personnel to the surface.
The expedition's initial findings are promising - the planet is perfectly suited to human habitation, and the only local life-forms appear to be harmless. The colonisation effort begins.
Five years pass.
A predator mothership arrives in-system, and is observing the humans. It spots the Colonial Marine escort to the expedition and sees an opportunity for good hunting.
The predators land on PL-129 and begin their hunt. The predator hunting party pursue one squad of marines into a research lab at the base of a mountain.
There is a battle in the caverns beneath the lab, where the marines try to hide, and the predators wipe out the marines. They leave to hunt elsewhere. After three days, a recovery team is sent to assess the damage to the laboratory. When they enter the caves, they discover a chamber that was breached by an explosion during the battle.
The chamber contained a clutch of Xenomorph eggs, the recovery team, not aware of what Xenomorphs are, are impregnated as they investigate the chamber. The aliens establish a hive in the research laboratory.
Soon fighting is taking place all across the island the human expedition had landed on, xenomorphs hunting for hosts, predators for trophies, and the humans desperately defending themselves from both species.