Append new test results to an existing newman report - postman

Question

I am using the following code snippet to run all collections in a folder using POSTMAN's npm module:
#!/usr/bin/env node
/**
* #fileOverview Read all collection files within a directory and run them
* in parallel.
*/
var newman = require('../'), // require('newman')
fs = require('fs');
fs.readdir('./examples', function (err, files) {
if (err) { throw err; }
//Filter all files with JSON file extension
files = files.filter(function (file) {
return (/^((?!(package(-lock)?))|.+)\.json/).test(file);
});
//Iterate on each file name and call newman.run using each file name
files.forEach(function (file) {
newman.run({
collection: require(`${__dirname}/${file}`)
}, function (err) {
// finally, when the collection executes, print the status
console.info(`${file}: ${err ? err.name : 'ok'}!`);
});
});
});
If I try using
{
collection: require(`${__dirname}/${file}`),
reporters: 'html',
reporter: { html: { export: './result/htmlResults.html', template: './templates/htmlTemplate.hbs' } }
}
instead of
{
collection: require(`${__dirname}/${file}`)
}
Every new collection run by newman.run will overwrite the report file htmlResults.html. I am looking for a way to append test data from new collections to the existing report. Is there a way to achieve this?
Note: I do not wish to create multiple report files(individual reports for each collection)