Earth- to Neptune-mass planets launch spiral density waves in gaseous protoplanetary disks and undergo type 1 migration. In isothermal disks, type 1 migration is inward and the migration timescale is inversely proportional to the planet mass. In radiative disks migration can be directed inward or outward, depending on the planet's mass and the disk's physical properties. For a given planet mass, there exist locations within the disk where the migration is convergent. We present results of hydrodynamic simulations of systems of planetary embryos of a few Earth masses embedded in radiative disks. We concentrate on the collective behavior of the system of embryos and their collisional growth.