Found it at Webster's Dictionary!
And the correct spelling is co-operative (with the hyphen!)

En el caso de que quieras decir que las distintas empresas se ocupaban de desarrollar todos los productos que producían

or for small outfits, "small enterprise clusters".

I've found many English documents on the Internet which use the Spanish term "empresas integradoras" instead of translating it. One of them (see first link) gives a definition similar to what you wrote in Spanish:

"Empresas integradoras are corporations owned by groups of small enterprises which provide services to their members, e.g., joint purchasing or marketing. Participating firms receive three types of incentive: first, a preferential tax regime; second, easy access to development bank loans; and third, preferential access to training programs (Alba Vega, 1997)."

Despite this widespread use of the Spanish term in English, I've found a connection between "empresas integradoras" and "enterprise clusters" (in the second link, "Enterprise Clusters" is part of the title of a book, and "empresas integradoras" is listed amongst the Key Phrases.)



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Note added at 1 día2 horas (2007-10-06 21:11:12 GMT)
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I have just noticed that the title of the first link is "How to promote clusters", so if the answer to your question is not "enterprise clusters", I'm pretty sure the correct answer will have "cluster" or "clustering" in somewhere.