Gov. Peter Shumlin pulled the plug last month on his plan to move toward a state-financed universal health care system -- citing "eye-popping" cost estimates -- but advocacy groups say they're not giving up the fight.On Thursday, Vermont Workers Center activists returned to the Statehouse to urge lawmakers to explore all possible options.It's the same group that disrupted the governor's inaugural address Jan. 8. Eventually, police made 29 arrests. Vermont has gone too far, they said, to abandon the goal of a "single-payer" health care plan. The group has demanded lawmakers hold public hearings and take an independent look at the economic modeling state health care economist Jonathan Gruber used which convinced Shumlin the price tag was too high to proceed -- at least for now. "If you change some decisions, look at some of the numbers differently, you can achieve the goal of universal publicly funded health care," state Sen. Anthony Pollina said at the Statehouse news conference. Pollina was part of a joint hearing held by the House and Senate Health Care Committees Thursday morning. They heard from four witnesses urging continued progress on health care reform."Members of the committee who thought we were done with it now know that for sure we can go forward -- we can do something," said Sen. Claire Ayer of Addison County, who chairs the panel. Further hearings are expected this winter, including one open for members of the public to weigh in. House Speaker Shap Smith has said the Legislature lacks the time or resources to do its own analysis of Gruber's modeling.Shumlin, meantime, has proposed a series of changes to improve Medicaid reimbursement rates for providers and additional cost containment efforts across the state. But Ayer said she believes Vermont can continue moving toward some kind of universal system, though full implementation may take longer than expected and require a series of incremental steps to contain costs.