Edinburgh and Glasgow will begin their Heineken Cup campaigns with ties against Saracens and Northampton Saints respectively.
Last year's semi-finalists Edinburgh will play host to the London side at Murrayfield on October 13.
Head coach Michael Bradley said: "We're very proud of what the club and our supporters achieved in last season's Heineken Cup."
He added: "Our task now is to plan with the same precision our assault on the 2012-13 competition."
Making up the rest of Pool One are Munster and Racing Metro 92.
Meanwhile, the Warriors' opener sees them travel to Franklin's Gardens on October 14, before also facing Ulster and Castres.
New head coach Gregor Townsend said: "We're facing finalists from the last two years, as well as one of the leading clubs in the French Top 14 clubs, so we know the quality that we'll be up against.
"But we know we'll receive incredible backing from our supporters at home and that will be a huge boost to our efforts in pushing through the group stages."