You need a specific scenario to explain why the two camps are separate and in rivalry and yet not once again at all out war with each other.
OTL, perhaps even if nuclear weapons had not existed maybe the West and Soviet camps might possibly not have come to blows anyway. But certainly The Bomb goes a long way toward explaining why that path was not taken over more than a generation.
Also, it is clear why, even if relations between the blocs had been less strained, they'd still have been quite distinct from each other; Cold War or Warm Peace, capitalist/liberal and Leninist socialist blocs would clearly be different worlds.
So that's why a Spartacist Germany is the easy way out to technically achieve your stipulation, EN, because if the "Central" bloc is in fact a Red revolutionary alliance of successor regimes, the nature of the ongoing conflict, even if hot war is avoided, is clear.
If on the other hand you mean, as I assumed you did, that the post-war CP is essentially a bloc of basically liberal capitalist states (perhaps distinctly less liberal and more aristocratic, but imagining that difference to be far more dramatic is imagining a very different Germany than existed before the war, so I assume not) then it is unclear why, if the conflicts between them and the Entente are so drastic as to make a divide, they don't just go to war again. And if not so drastic, presumably the Concert Of Europe keys up its orchestra again and the various states start horse-trading and soon the alliances are reconfigured out of all recognition.
In any event, if a state of peace exists, and both sides are left in a comparable economic state, trade presumably resumes, businessmen cross state lines, it's hard to see a hard bloc division persisting.
So that's what you have to give us--a specific scenario that shows how Europe gets divided in the peace in a way that reasonably would persist, when the regimes on each side of the line are essentially mirror images of each other.
Or of course, default to Spartacist or proto-Nazi Germany. Or heck, assume it's the Entente nations that diverge in some radical direction and that it's the CP nations that muddle along as liberal capitalist societies.