What are refugee groups?

It is not related to Chemistry, but I'd try answering your question

Refugee groups, or should say refugees, are defined as owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group, or political opinion, is outside the country of their nationality, and is unable to or, owing to such fear, is unwilling to avail him/herself of the protection of that country". (according to the 1951 United Nations Convention Relating to the Status of Refugees)

It is not useful to copy all the information to here, but you could refer to the Wikipedia articles in English (http://en.wikipedia.org/wiki/Refugee) or Chinese (http://zh.wikipedia.org/wiki/%E9%9A%BE%E6%B0%91)

難民集團,吉普賽人,遊牧民族,弱勢多數,失敗者聯盟.