What is the connection between the SJ's and the Xeno?

The engineers are "engineering"...Duh! They engineer lifeforms...why, what or for whom are the big question(s) that only the release of Microsofts next big software launch tie in with Prometheus 2 can reveal I'm afraid:O)

I think it could be that the Jockeys tried to acquire and use the Xenos as a bio-weapon; much like how the company wanted to acquire the alien. It didn't work out so well for them, so they altered their strategy and came to fear/worship that form of the creature. It could be that the company is destined to repeat the engineers' mistake in trying to use the alien. I think the Engineers were already involved in bioengineering. Then, the Engineers/Jockies played with fire and got burnt but managed to use the genetics from some of the specimens for their own creations. The genetic material was possibly mixed and diluted enough to create a form of the xenomorph that could be controlled by the Engineers. Or so they thought...

Well we dont know for sure, there are many inconsistancies in what is being said from Ridley and co etc.... Its all a bit unexplained, yes it would seem they know of the Xeno prior... of Prometheus, is the Mural a warning... we just dont know. Ridley on one hand keeps talking about the SJ as guys in suits and that this is the reason behind this movie as he wishes to explore them. He keeps saying that the Derelict was maybe a Bomber carrying Bio Weapons, he also keep saying that the Eggs was the ships Cargo and it landed and never crashed. He even then went as far to say the Technology and Derelict is maybe Millions of years old.... Looking at the dead Jockeys and the Hollogram scene we could assume that the Engineers have had a encounter with the Xenos in the past and it was a experience they wish they never encountered as it could be what caused much of the demise of their race... But then Ridley also said this movie is where Mommy meets Daddy, is he saying that in context of the Xeno? So we just dont know, Ridley can send us on a merry go round and we wont know the truth untill we see the movie and then after we may still have no answers but even more questions... Dont forget Damon Lindelof helped develop the final Script so we just dont know what to expect.... And Smurfs kiddnapping the Gringe and breeding him with Magic Johnson could be what created the Jockeys and why Magic Johnson seemed imune to AIDS... Thats sound just silly and stupid and makes no sence but you can bet some of the stuff Lindelof would come up with would be even more stupid. I have a major concern about him having anything to do with this movie.

^^^ Basically what Mala’kak said. The eggs are "cargo" on the 1979 Derelict. That implies that they are very valuable for some purpose. We know that they are very effective as weapons/killing; including a very destructive method for reproduction. That corroborates everything above from him.

@Mostly I think you might be on the right track. I like to think I'm the school who believes that Sir Ridley Scott meant what he said when he said that the original Xeno as a shape was used-up and done with and that by this he actually means to introduce a new creature or a new antagonist in Prometheus if you will, thus it more than likely seems to be the case here. As far as a connection to the former Xenos or to the Derelict from 1979 might just be a proverbial footnote in the greater scheme of things. Let's not forget that Scott has maintained the same notion trough the years, that the Derelict is a bomber/carrier of some kind and that the eggs are it's cargo, and yes I know that things are not set in stone but I think he's genuine in this case.

The relationship could be: Cargo to Pilot Pet or Slave to Master Experiment to Scientist Weapon to Engineer or any mix of those things. Really, those are just about the only possibilities outside of coincidences.

Another possibility just hit me, it could also be that the Engineers created their own idols for worship.

or... the engineers clean the indigenous life (xenos) off earth so they could plant their creation (humans) on earth. and were transporting the eggs back o thier home world for study/future projects when one got loose and "hugged" the pilot, he then emergency lands his ship and puts a warning beacon out as he is getting chest bursted...