How to combine all the words of a sentence extracted with a regex?

I would like to combine with a linux command, if possible, all the words that start with a capital letter, excluding the one at the beginning of the line. The goal is to create edges between these words. For example:

My friend John met Beatrice and Lucio.

The result I would like to have should be:

• John, Beatrice
• John, Lucio
• Beatrice, Lucio

I managed to get all the words that start with a capital letter, excluding the word at the beginning of the line through a regex. The regex is:

*cat gov.json | grep -oP "\b([A-Z][a-z']*)(\s[A-Z][a-z']*)*\b | ^(\s*.*?\s).*" > nodes.csv*

The nodes managed to enter them individually in column, ie:

• John
• Beatrice
• Lucio

The goal now is to create the possible combinations between names that start with a capital letter and put them into a file. Any suggestions?

Here is another awk script doing the task, building the output while reading input.

script.awk allowing duplicate names.

BEGIN {FPAT =  " [[:upper:]][[:alpha:]]+"}
{
    for (i = 1; i <= NF; i++ ) {
        for (name in namesArr) {
            namePairsArr[pairsCount++] = namesArr[name] $i;
        }
        namesArr[namesCount++] = $i;
    }   
}
END {for (i = 0; i < pairsCount; i++) print namePairsArr[i];}

If duplicate names not allowed, script.awk is:

BEGIN {FPAT =  " [[:upper:]][[:alpha:]]+"}
{
    for (i = 1; i <= NF; i++ ) {
        if (nameSeenArr[$i]) continue;
        nameSeenArr[$i] = 1;
        for (name in namesArr) {
              namePairsArr[pairsCount++] = namesArr[name] $i;
        }
        namesArr[namesCount++] = $i;
    }
}
END {for (i = 0; i < pairsCount; i++) print namePairsArr[i];}**

run

awk -f script.awk gov.json > nodes.csv

sample input file:

My friend John met Beatrice and Lucio
My friend Johna met Beatricea and Lucioa

sample output:

 John Beatrice
 John Lucio
 Beatrice Lucio
 John Johna
 Beatrice Johna
 Lucio Johna
 John Beatricea
 Beatrice Beatricea
 Lucio Beatricea
 Johna Beatricea
 John Lucioa
 Beatrice Lucioa
 Lucio Lucioa
 Johna Lucioa
 Beatricea Lucioa