North Attleborough (Mass.) Contributory Retirement System plans to add a $5 million to $10 million allocation to active domestic fixed income, confirmed Debra Bush, board administrator. Officials of the $60 million plan will consider core-plus, convertible, high yield and global bond strategies. They have not yet determined a source of funding. The plan has about $12 million in a core fixed-income portfolio run by RhumbLine Advisers and $9 million in a core-plus portfolio managed by Voyager Capital. Consultant Dahab Associates assisted.