Gouramis spawn on leaves at the surface ywork so fish can eat the eggs from below. Putting a coke bottle over the top would not help in this case.
You could try slowly moving a container underneath, so as not to disturb the nest, and lift the lot out. Otherwise I would just leave it and see what happens.
If you want to try breeding them, put them in a separate tank, make sure there are leaves on the surface they can use to help hold their bubblenest together and make sure the water surface is calm.