FCm Travel Solutions has signed DER Business Travel as its exclusive partner in Germany.
On the back of the agreement, the two travel management companies (TMCs) also plan major expansion in 11 countries of central and eastern Europe.
The deal cements a partnership between TMCS which are among the largest in their respective countries.
DER, part of the Deutsches Reiseburo group, ranks second in Germany behind BCD Travel (now owners of TQ3) with 90 centres nationwide and annual gross sales of €680m.
FCm, which last year took over Alan Spence's company Britannic Travel, then a franchisee of the TQ3 group, ranks fourth in the UK with an annual turnover of £285m.
Mr Brian Donnelly, FCm's regional director EMEA, said the two TMCS had been talking for two years but at the time, DER was happy to be part of the Synergi group. The situation changed when Synergi was taken over by The Travel Company (now part of BCD Travel).
He said the two companies were a "cultural fit" and that one of DER's strength's was that it was independent.
"German clients still want a German travel agent and DER has had a lot of success because they had not been taken over by anyone," he said.
FCm in the UK already has several German/multi-national companies as clients, including Volkswagen, T-Mobile and Daimler-Chrysler. Among DER's clients are Siemens, KPMG, PricewaterhouseCoopers, Deutsches Post and the UK-owned Vodafone.
The 11 countries where FCm/DER plan to expand are Austria, Switzerland, Poland, Romania, Hungary, the Czech Republic, Slovakia, Bulgaria, Latvia, Estonia and Lithuania.
Mr Donnelly said they planned to set up a regional management group in which DER will be the lead player.
"Most other companies work in three regional, EMEA, APAC and North America but we find what works for us is a cluster of about ten countries," Mr Donnelly said.
It would be a strategic steering committee of about six people from FCm, DER and some of the other countries and which would offer direction and guidance to the 11 countries.
He said that with the break up of the USSR, Germany and Lufthansa had opened up new markets, far more than BA, which offered numerous opportunities.
Under the deal, DER will drop its logo and the new grouping will be branded, initially, as FCm DER Travel Solutions in Germany but purely as FCm Travel Solutions in the other countries.
DER managing director Ralph Osken said: "This agreement means we will be able to offer our customers high quality help worldwide."
Mr Donnelly said that in Europe, FCm's next stage would be expansion in both the Baltic and the Balkans where it already has a centre in Ljubljana, Slovenia.
But he also said it would be taking another look at France where currently American Express and Carlson Wagonlit Travel dominate.