Blizzard EVP of design Rob Pardo's told Edge the company is open to sharing insight with Bungie if the developer is making an MMO.
The genre of the first game the developer's making with Activision under a new ten-year deal is unknown.
But with Blizzard under the Activision roof, and if Bungie is making an MMO, Pardo says it's something it could advise on to the developer.
"There are a lot of ifs there. It would have to be a very specific proposal," Pardo said over the weekend at Blizzcon.
"Blizzard are very focussed on our own stuff and I think one of the reasons that we're successful is because we don't get distracted.
"That said, Activision is in the family and Bungie is doing stuff for Activision. If they called us up and wanted some advice or wanted to have a conversation, absolutely, but I do that with a lot of my game developer friends throughout the industry."
Pardo added: "As far as something specific, like if they were going to do an MMO would we somehow do customer service for them? Wow, that's, like, really far out there. I really have no idea - that's a lot of speculation. It's possible, I guess."
Blizzard's next MMO, according to Pardo at Blizzcon, won't get a reveal until 2012 at the earliest.