diff --git a/src/main/webapp/resources/js/base/upload-support.js b/src/main/webapp/resources/js/base/upload-support.js
index 45e6fba..9c4f27e 100644
--- a/src/main/webapp/resources/js/base/upload-support.js
+++ b/src/main/webapp/resources/js/base/upload-support.js
@@ -126,6 +126,29 @@ var download = {
 	}
 };
 
+function getBundles(array, keymapper, size = 50) {
+	let byKey = array.reduce((result, item) => {
+			let key = keymapper(item),
+				items = result[key];
+			if (!items)
+				result[key] = items = [];
+			items.push(item);
+			return result;
+		}, {}),
+		bundle = [];
+		bundles = [];
+	for (let items of Object.values(byKey)) {
+		bundle = bundle.concat(items);
+		if (bundle.length < size) continue;
+		
+		bundles.push([].concat(bundle));
+		bundle.splice(0);
+	}
+	if (bundle.length > 0)
+		bundles.push(bundle);
+	return bundles;
+}
+
 function upload(options) {
 	options.enctype = "multipart/form-data";
 	options.processData = options.contentType = false;