Is there a way to link the fill color of an object(s) to the fill color of another Object?
For example, if the fill color of objects X, Y and Z were linked to Object A.... then changing fill on Object A would also change X,Y, and Z.

Or, how else to reach this goal of linking an objects color to another object?

thanks

Yes, there is.

This feature is called a custom swatch in Inkscape, see this tutorial: http://goinkscape.com/custom-color-pale ... -inkscape/
and the corresponding part of the manual: http://tavmjong.free.fr/INKSCAPE/MANUAL ... omSwatches

Sounds like cloning to me. You change the color of the original all the clones change.

Cloning will also keep the shape and all other properties of the original object, not just its color.
Which functionality you want to use depends upon whether you've got a set of (near-)identical objects, or if you want different objects share the same color.

I guess this is again the problem of another new OP not explaining his goal with enough information.

'Select same' also comes to mind, but as long as its unclear what OP has in mind, its just guessing.