The phrase "already been collaborating" is correct and usable in written English.
It can be used to indicate that collaboration has been taking place prior to the current moment or context.
Example: "We have already been collaborating on this project for several months, and the results are promising."
Alternatives: "previously collaborated" or "been working together."
The pair had already been collaborating fruitfully, finding that her dogged pursuit of data and his more theoretical public policy eye were well matched.
The HMSC encompasses six partner museums: the Museum of Comparative Zoology, the Harvard University Herbaria, and the Mineralogical and Geological Museum (which have already been collaborating as the Harvard Museum of Natural History), and the Semitic Museum, the Peabody Museum of Archaeology and Ethnology, and the Collection of Historical Scientific Instruments.
The group will become a part of RELX's Risk & Business Analytics, which is part of the LexisNexis Risk Solutions group and already works in areas of fraud and authentication, and had, in fact, already been collaborating with ThreatMetrix.
Greenwald and Scahill have already been collaborating on NSA coverage, too.
By the time Coronel's phone number was handed over, Scalpel had already been collaborating with the DEA for five months.
Monsanto's G.D. Searle drug division already is collaborating with Pfizer to promote and distribute Searle's new arthritis drugs.
You may already be collaborating with a few freelancers, but your agency will need to invest in full-time employees.
Much has been achieved already, as the tea industry has been collaborating for almost 20 years.
Reporters, already mired in the phone-hacking scandal, had been collaborating with convicted prisoners.
I had been collaborating with Allan Bradley (now leader of the Mouse Genomics Team at The Wellcome Trust Sanger Institute, Cambridge, UK) who was already at BCM.
"My participation has been collaborating.
