The open field system reminds me of Skyforge.
It's similar in the fact that big flying text at the sector barriers appears, yes. But other than that, they work similar to Bethesda "Cells" or World of Warcraft's progression-phased areas where they unload/load/phase player characters/etc. as they go between them. At least that's what the explanation alluded to. Which is probably why those other player characters were standing just inches prior to going past the sector change.
I have a feeling Party Beacons are going to be cut from NGS in favor of better menus/etc.