More than 300 physicians and other health-care providers owed money by Greater San Diego Health Plan, the troubled health maintenance organization operated by parent firm Western Health Plans, agreed to a 30-day moratorium on payments. In agreeing to the moratorium, the providers selected a creditors committee of 13 primary care physicians, specialists and hospital representatives. The company reported a loss of $7.1 million for the nine months ended March 31 and said losses will continue during the fourth quarter ending June 30. The company said that the company had a deficit in shareholder equity of more than $16 million as of last month. On Thursday, Western Health Plans said it has received an unspecified bid from PacifiCare Health Systems of Cypress to buy certain of Western's assets. The two companies began negotiations Friday. In American Stock Exchange trading Friday, Western Health Plans stock closed up 18 cents at 87.5 cents a share.