Hi Thom,

with a little guide from TIG here, I manage to update this plugin.

I have no knowledge about ruby , not even a basic grammer , but as I am familiar with other languages like php and C++ , I just gone through the some ruby resources and made this modification.
Some minor changes is required as when trying to replace the default material , it is replacing whole model.

I am attaching both modified code and skp test file, hope you rectify this minor bug .

http://sketchucation.com/forums/viewtopic.php?f=323&t=55340

default material change bug using Material Replacer(Mod)

I think this plugin can be updated to make this function possible.
More details:
window frames with different sizes say 4'x3', 2'x3, 5'x2' are present which has same wooden texture(teak). Using this plugin if 4'x3' selected as source material then all other group/model with same dimension(ultimately volume) can be replaced with other material(oak) and other frames should remains unchanged.

Is there plugin which applies the material/texture to groups of same volume.

The idea is similar to coreldraw's "copy properties from", in which it will ask for source object from where properties has to be copied.

why volume?
It can be applied by group's name also but it might be possible that after making cloning of groups some of them might be intentionally modified(but name of that group might not been changed) in size.

where it can be use?
usually where groups/models are cloned ex. windows,doors,windows glass etc.

when try to apply putonlayer to nested group element, something strange happening as sub groups are toggling between layers.

steps to reproduce
apply punonlayer to top group element and set to layer "first"
toggle the visibility of layer "first"
apply punonlayer to bottom group element and set to layer "ground"
toggle the visibility of layer "ground"

Tried with both PutOnLayer_bmw_wrh.rb and PutOnLayer_sortname.rb and sketchup pro 2013

putonlayer's sub group toggling problem