It means you cannot tell they're members, unless they're members of the main group.

只是表明您不能说明它们是成员，除非它们是主组的成员。

youdao

Otherwise, you may add someone to the main group who's already in a breakout subgroup.

否则，可能会将断接子组中已经存在的某人添加到主组中。

youdao

In September,a power struggle erupted in violence in the lower Juba region between al-Shabab and Hizbul Islam, a clan-based Islamist-nationalist group which had been al-Shabab's main ally in its year-long battle to overthrow the U.N.-backed government in Mogadishu.

VOA: standard.2010.01.02

Further proof came in another story making waves in Strasbourg, the departure of British Conservatives from the main centre-right group, the European People's Party (EPP).

ECONOMIST: Charlemagne

Modeled deliberately on the American-Israel Public Affairs Committee (AIPAC), the main pro-Israel lobbying group, the CANF changed American policy toward Cuba.

CENTERFORSECURITYPOLICY: The Man Who Lived to Save Cuba

Kidal - home of the head of Ansar Dine, the main militant group in northern Mali - was bombed overnight by French forces, Malian officials say.

BBC: Mali crisis: French-led troops 'surround Timbuktu'