yes! The UV layout can be treated simply as a canvas, you can use different parts of that canvas for different objects.

Plan where you want the different parts to be and lay the UVs out for each separate object. carefully so that you won't introduce overlaps.

The fun bit comes if you want bake procedurals or export the UVs, in which case you will need to do it for each object and then paste together in your paint package.

The only question I would have is why do you want to do this? - is it that objects are very interwined and you want to continue maps over from object to object seamlessly? if this is the case you may be better off booling / joining the objects together?

or is for some other constraint?

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Toolset: Blender, GIMP, Indigo Render, LuxRender, TopMod, Knotplot, Ivy Gen, Plant Studio.