Foliage draw calls?

We have the following case, a densely populated foliage over the landscape.
As I understand so far, the number of draw calls is related to landscape component size and cull distance, ie indentical foliage instanced mesh takes as many draw calls as cull distance covers landscape components in the field of view (take in count that every lod a different mesh also).
So we have a case where the draw calls number decreases when we increase the landscape component size even though then we have some other unwanted side effects.
Theoretically the smallest draw calls number would be if the whole landscape were one component.
My question is the following, is it possible and how (world composition is also considered)?:
Set the foliage to primary landscape, Add another proxy landscape to the level (is not visible, placed below primary for example) that has only one component, and is scaled to the dimension of the primary landscape.
Copy foliage from the primary landscape to the proxy landscape while retaining the transform coordinates.
The goal of course would be to have each individual instanced foliage mesh have only one draw calls per level.
Although I haven’t tested enough, the calculation tells me that this would drastically reduce the draw calls number in these specific cases.