This, they say, would result in a Europe with an "inner circle," the EU, with deep integration, and an "outer circle" containing the UK, with less integration.
Over the long-run, this could also "serve as a vision" for structuring relations with Turkey, Ukraine and other countries.
These are among the main conclusions of a policy paper drafted by the five-strong group and launched in Brussels on Monday.
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This comes a day before UK Prime Minister Theresa May is due to chair a key meeting at Downing Street of senior government ministers on the upcoming Brexit negotiations.
Ahead of the meeting, one of the authors, Guntam Wolff, director of Bruegel, a leading Brussels-based think tank, told this website, "Brexit is now a reality. It carries risks but it can be turned into an opportunity."
The detailed paper, called 'Europe after Brexit', said the British vote to withdraw from the EU marks a "major constitutional change" for the UK and a "significant rupture" for the EU.
"Our proposal," it says, "is to turn the rupture into an opportunity to reorganise Europe in two circles. The inner circle constitutes the EU with political aims and supranational constitutional structures."
The paper, seen by this website, says, "The outer circle, of European cooperation, adding countries not in the EU would have more flexibility and be based on an intergovernmental structure, the Continental Partnership (CP).
"Most important, CP countries would not participate in the freedom of movement of workers, would not share the political commitment to ever closer union."
Wolff added, "I think the UK should strive for a deep integration that looks close to the single market.
"Most important is the single set of rules and the unique enforcement by ECJ, otherwise services sector integration in particular cannot be sustained."
The paper is the outcome of a dialogue among the five authors during the summer and was published simultaneously in London, Brussels, Berlin and Paris.
As well as Wolff, the drafters are: Jean Pisani-Ferry, Commissioner General at France Stratégie and Professor at Hertie School of Governance; Norbert Röttgen, Chairman of the Foreign Affairs Committee of the German Bundestag; André Sapir, Professor at the Université libre de Bruxelles and Senior
Fellow at Bruegel and Paul Tucker, Chair of the Systemic Risk Council and a Fellow at Harvard University.
The paper reads, "Our proposal requires the UK and the EU to make tough choices. The UK will have to answer the question of whether it wants to continue to maintain close economic cooperation with the EU and whether it wants to maintain and potentially even strengthen its engagement in security and, conceivably, defence matters. This is ultimately a political choice that must be spelled out unambiguously."
The EU, it states, "will have to agree among its members to put aside punitive motives and reach an economic settlement that grants control over labour mobility to the UK while allowing continued access to and participation in important parts of the single market.
"This is a political choice on which clarity is needed. The EU countries will also need to reflect on whether this model would be adequate for other neighbouring countries."
The five authors note, "Our proposal is driven by the firm belief that neither the EU and its member states nor the UK have an interest in an escalation of tensions or costly disengagement following Brexit.
"Neither the UK nor the continuing members of the EU can escape their geographical interdependencies. Both have a stake in economic and political stability in Europe.
"Today's volatile and dangerous world requires its nations to collaborate to confront new and multiple challenges. The longer-run prospect of a future world in which Europe is only one among many powerful regions demands the same."
Speaking at a news conference to launch the document, Wolff added, "We hope that our proposal can provide a benchmark, even a vision, for the undoubtedly difficult negotiation that lies ahead."
He added, "Brexit is a reality in the sense that a referendum has happened. The UK voters have in effect rejected the supranational institutions of the EU and, in particular, the political integration that free movement of workers and opening the labour market to 510 million citizens represents.
"But it makes sense for the EU and the UK to search for new forms of collaboration that respect the referendum. Europe cannot afford excessively large economic and political losses in the current volatile world.
"Our proposal would involve controls on free movement of workers. In turn, rules and the enforcement of laws will remain in order to protect and maintain a deeply integrated single market.
"Politically, the UK would also get a voice in the law-making but ultimate formal authority would remain with the EU."