Building several water droplets in oil.

Hi there,

I am trying to investigate the effect of water content on properties of oil. I need to build a model contain several water droplets in oil (shown as the picture 1). Now I can use different isosurface to pack water molecules, but I cannot pack the oil molecules as the framework contains more than one isosurface (shown as the picture 2). Does anyone know how to build such a model? Many thanks.