assemble both parts into an assembly. Select, Modify, Modify Part (select the part WITHOUT the surface), Feature, Create, Surface, Copy (select the surfaces from the part WITH the surfaces), Done Return, Done, Done ect...
Now open the part & the copied surfaces will be there, but remember, they can only be modified in the assembly, so SAVE the assembly.
This is the method I use because I don't have the advanced assembly module. I know there are other methods of doing this, but this is my method.
You can also use a Copy Geom feature, which allows you to copy lots of different types of entities, not just surfaces, e.g., curves, edges, points, axes, datum planes, copy geom features, publish geom features,etc. The other big advantage is you can toggle dependency on and off.