или
ассоциация (обще)национального уровня

--------------------------------------------------
Note added at 50 mins (2004-11-03 06:15:25 GMT)
--------------------------------------------------

Пример:
в Канаде в каждой провинции (в США в каждом штате) есть местная орг-я переводчиков, которая состоит в (обще)национальной ассоциации СTTIC(в США это АТА).


CTTIC (в США ATA) - это пример national umbrella body
The Canadian Translators, Terminologists and Interpreters Council, generally recognized as the ****national body*** representing professional translators, interpreters and terminologists, contributes to high quality inter-language and intercultural communication.

CTTIC has no individual memberships. Since professional organization is a matter of provincial and territorial jurisdiction, CTTIC admits only provincial and territorial bodies, variously called an association, order, society or corporation. Its total membership consists of the eleven member bodies which, in turn, represent their own members.