By Amanda Becker and Luciana Lopez

WASHINGTON/PHILADELPHIA (Reuters) - Hillary Clinton's White House transition team, a mix of former advisers of President Barack Obama, close confidants, long-time colleagues and former elected officials, reflects the sense of careful organization the Democratic candidate has aimed to project in her presidential campaign.

But her Republican rival, Donald Trump, could seize on the group to make the point that she is part of the establishment he aims to defeat in November's election, and to reiterate his charge that a Clinton administration would be an Obama "third term."

The group, which the Clinton campaign named on Tuesday and which will lay the groundwork for her to take charge quickly if she wins, is evidence of Clinton's long experience in Washington as a former secretary of state, U.S. senator and first lady.

Transition teams aim to help the president-elect make key decisions during the period between the election and the inauguration, in this case from Nov. 8 to Jan. 20, so the new White House occupant can fill leadership posts quickly.

"They are the names you would expect – people who have been advising her for a long time; people who have worked with her for a long time and people who are peers, who she respects," Matt Bennett of the moderate Democratic group Third Way said of Clinton's transition team.

The group will be headed by Ken Salazar, a former interior secretary and U.S. senator. He will lead four co-chairs: former Obama national security adviser Tom Donilon; former Obama aide Neera Tanden, who now leads the progressive think tank the Center for American Progress; former Michigan Governor Jennifer Granholm and Maggie Williams, the director of Harvard's Institute of Politics.

Heather Boushey, the executive director of the Washington Center for Equitable Growth, will be the chief economist. Two additional policy advisers from Clinton's campaign, Ed Meier and Ann O'Leary, will also move full-time to the transition team, the campaign said in a statement.

The transition team does not necessarily reflect future policy.

"The job here is to give options, not just say there is one policy course you want to take," said Democratic strategist Bob Shrum, who advised the presidential campaigns of Al Gore and John Kerry.

Clinton would be the first woman elected to the U.S. presidency and Shrum said Clinton's team "has got to be the first transition team in history where the majority of its members are women."

Shrum added that Clinton is largely following Obama's template as he prepared for his transition after the 2008 election.

Tanden, who played a key role in shaping Obama's health care overhaul, is a member of Clinton's tight-knit inner circle, and has also worked for her husband, former President Bill Clinton.

Williams was the 1992 transition director for Clinton when she became first lady, and then her chief of staff in the White House.

Clinton worked closely with Donilon when she led the State Department from 2009-2013. Granholm, the former governor, is also a former state attorney general and has years of experience in Democratic politics.

The Progressive Change Campaign Committee applauded the selection of O'Leary and Boushey, praising their economic positions. The environmental group Greenpeace criticized Salazar for not curbing fracking in his home state of Colorado.

The announcement of the team came as Clinton has gained momentum in the opinion polls, with the current RealClearPolitics average of national polls showing her 6.7 points ahead, at 47.7 percent to Trump's 41 percent.

Trump's campaign has struggled after he made a string of controversial remarks since formally winning his party's nomination last month.

More establishment Republicans, alarmed by Trump's inability or unwillingness to rein in his provocative remarks, have distanced themselves from the candidate in recent weeks. The Wall Street Journal, a leading conservative voice, said in an editorial on Monday that he should fix his campaign in the next three weeks or hand over to his running mate, Indiana Governor Mike Pence.

Trump, a New York businessman who has never held elected office, picked New Jersey Governor Chris Christie to head his transition team in May.

(Additional reporting and writing by Doina Chiacu; Editing by Frances Kerry)