Retailers preparing to open their doors in the new Assembly Row development will begin hiring new employees at four job fairs beginning this weekend. Legoland Discovery Center and AMC Theatres are two of at least 15 businesses that will participate in the hiring fairs on March 1, 2, 8, and 9 in the East Somerville Community School at 50 Cross St. Only Somerville residents will be allowed to attend the first two job fairs, scheduled for Saturday from 10 a.m. to 3 p.m. and Sunday from 2 to 7 p.m. . The job fairs are being hosted by the city of Somerville and Assembly Row developer Federal Realty Investment Trust. Legoland Discovery Center will be looking to hire more than 100 employees, said David Gilmore, the general manager, in a joint press release with the city and Federal Realty. Other businesses in Assembly Row that will participate in the job fair include Pendleton, Brooks Brothers, Chico’s, Fuji, Wilsons Leather, Papagayo, Tony C’s, J.P. Licks, Puma, the Nike Factory Store, Le Creuset, Sports Authority, and Starbucks. Organizers are expecting more businesses to be added to the list.