bl_info = {
# ...
}

if "bpy" in locals():
    import imp
    imp.reload(op1)
    imp.reload(op2)
else:
    from . import op1
    from . import op2

import bpy

def menu_func(self, context):
    self.layout.separator()
    self.layout.menu(op1.Operator_1.bl_idname)
    self.layout.menu(op2.Operator_2.bl_idname)


def register():
    bpy.utils.register_module(__name__)
    bpy.types.VIEW3D_MT_uv_map.append(menu_func)

def unregister():
    bpy.utils.unregister_module(__name__)
    bpy.types.VIEW3D_MT_uv_map.remove(menu_func)


if __name__ == "__main__":
    register()