Giving in to pressure from advocates and Democratic legislators, Republican Connecticut Gov. M. Jodi Rell said that her struggling Charter Oak plan for the uninsured can succeed even when medical enrollment is separated from the popular HUSKY health program for children. Rell will no longer require HMOs that want to participate in the HUSKY plan to join her signature program for uninsured people. The demand for a package deal had inspired few doctors and hospitals to participate in Charter Oak, and the program has clearly displayed growing pains as it tries to become established, advocates and legislators say.