A new deal struck between 14 countries on Friday says that couples of different European nationalities will be able to choose which divorce laws will apply to them.
The breakaway pact marks a significant extension of the process that allowed an inner core of European Union countries to set up the euro currency, or others to remain outside the continental border-free Schengen area.
It raises the prospect of various groups of like-minded European nations going their own way in different areas of law in future.
"The proposal would allow (couples) to know in advance which law is applicable to their divorce.
"It would increase flexibility and autonomy by giving spouses a possibility to choose the applicable law to their divorce or legal separation and it would set clear rules for cases where no law has been chosen."
One EU official said there is a "momentum reminiscent of the move to set up the euro.
"If we were to wait for everybody to come on board, we could have been waiting forever," he said.
The European parliament has still to pass the deal, but from a group of eight countries originally two years ago, another six have since joined up.
The full list is: Austria, Belgium, Bulgaria, France, Germany, Hungary, Italy, Latvia, Luxembourg, Malta, Portugal, Romania, Slovenia and Spain.
While countries including Britain chose to remain outside the group, they nevertheless gave the nod to the agreement.
The system of "enhanced cooperation" was introduced under the Lisbon Treaty which finally entered force in December last year after years of political wrangling.
Supporters claim that applying the system in this area could potentially slash lawyers' fees for divorcees in these countries.
Originally, backers wanted to clamp down on so-called 'divorce shopping,' where nationality or the place where a marriage took place can give one spouse an unfair advantage.
Critics, though, say the system will end up creating rings of 'Europe within Europe.'
Sweden previously blocked attempts to harmonise divorce law across the 27 EU states.
Some 140,000 divorces each year will be affected.