"I think after this week we'll see more," he said, adding that if the group could grow to about 75 it would be a critical mass.
Rep. Janice Hahn, a California Democrat, said her immediate goal is to "bring a friend" to the next No Labels meeting on the Hill.
Maine Sen. Angus King, a two-term governor just elected to Congress, is an independent who will caucus with Democrats. He said he's not sure if the group can build itself into an effective force.
"But I think the feeling is we've got to try something," he said.