Searching for Private Gordon

While exploring a remote cemetery overlooking the Island of Jura during recent holiday to Argyle (I know, a strange holiday pastime), I stumbled across this particularly solemn cenotaph.
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It was erected by Hugh and Christina Graham of Achahoish in memory of their fours sons Edward, Hugh, Colin and Arthur, who were killed in action during the 1st World War. 

Remarkably, two of the brothers (Hugh and Colin) were members of New Zealand regiments, while the others (Edward and Arthur) fought with the Argyle and Sutherland Highlanders.

I've began to do some research and would like to hear from anyone who knows anything about the family behind this tragic memorial, which is located in the Carsaig Cemetery near Tayvallich.