KIND OF SPOILER AHEAD for RHATO
Batman, Superman and Wonder Woman: The first and most known Trinity.
Nightwing, Donna Troy and Supergirl?: Dick and Donna don't really have a Kryptonian to fill the gap. Kara is the closest that fits the bill as she's been around for awhile too. I suppose you could say she's closer to Barbara in some canon but that grouping would still need an Amazon. Dick and Donna previously had this incredibly strong bond that felt like they were pretty much siblings. He even gave her away at her wedding. That closeness is probably going to return.
Red Hood, Artemis and Bizzaro: The "Dark" Trinity. We know Jason will bond over being an "abomination" with Bizarro (due to his return from the dead) but not much else.
Red Robin, Superboy (Kon/Conner Kent), Wonder Girl: I have no idea what the current state of their friendship is. They were all close despite the love triangle being teased more than once. Will Conner get a new code name now?
Robin and Superboy (Jon Kent): No Amazon for the boys to hang out with at this time. No idea what their dynamic will be like until their introduced.