--- a/installer/schema/eventtracker.yml
+++ b/installer/schema/eventtracker.yml
       order: '100'
       visby: {  }
       editby: {  }
+      validation: requiredfromgroup
+      validation_param: presentergroup
+      validation_message: 'Please specify at least one presenter'
       flags:
         - public
   -

--- a/lib/core/Services/Tracker/Controller.php
+++ b/lib/core/Services/Tracker/Controller.php
@@ -466,6 +466,7 @@ class Services_Tracker_Controller
 				'regex' => tr('Regular Expression (Pattern)'),
 				'username' => tr('Username'),
+				'requiredfromgroup' => tr('Required From Group'),
 			],
 			'types' => $types,
 		];

--- a/lib/validators/validator_tiki.js
+++ b/lib/validators/validator_tiki.js
@@ -216,6 +216,21 @@ function process_submit(form, event) {
 	return true;
 }
 
+jQuery.validator.addMethod("requiredfromgroup",	function(value, element, options) {
+		var groupclass=options;
+		var isvalid = false; // default to fail validation
+		jQuery('.'+groupclass).each(function (index, value){
+			if($(this).find('input').val()!=''){
+				isvalid = true;
+			}
+		});
+		if(isvalid == false) jQuery('.'+groupclass).find('input').addClass('is-invalid');
+		else jQuery('.'+groupclass).find('input').removeClass('is-invalid');
+		return isvalid;
+	},
+	jQuery.validator.format("At least one of these fields are mandatory.")
+);
+
 jQuery.validator.addMethod("validate_cron_runtime", function (value, element, options) {
 	var cronTime = value.trim();
 	var regex = "^(\\*|((\\*\\/)?[1-5]?[0-9])|[1-5]?[0-9]-[1-5]?[0-9]|[1-5]?[0-9](,[1-5]?[0-9])*) (\\*|((\\*\\/)?(1?[0-9]|2[0-3]))|(1?[0-9]|2[0-3])-(1?[0-9]|2[0-3])|(1?[0-9]|2[0-3])(,(1?[0-9]|2[0-3]))*) (\\*|((\\*\\/)?([1-9]|[12][0-9]|3[0-1]))|([1-9]|[12][0-9]|3[0-1])-([1-9]|[12][0-9]|3[0-1])|([1-9]|[12][0-9]|3[0-1])(,([1-9]|[12][0-9]|3[0-1]))*) (\\*|((\\*\\/)?([1-9]|1[0-2])|([1-9]|1[0-2])-([1-9]|1[0-2])|([1-9]|1[0-2])(,([1-9]|1[0-2]))*)) (\\*|((\\*\\/)?[0-6])|[0-6](,[0-6])*|[0-6]-[0-6])$";

--- a/lib/validatorslib.php
+++ b/lib/validatorslib.php
@@ -85,7 +85,7 @@ class Validators
 						$validationjs .= 'required: true, ';
 					}
 				}
-				if ($field_value['validation']) {
+				if ($field_value['validation'] && !in_array($field_value['validation'], array('requiredfromgroup'))) {
 					$validationjs .= 'remote: { ';
 					$validationjs .= 'url: "validate-ajax.php", ';
 					$validationjs .= 'type: "post", ';
@@ -120,6 +120,8 @@ class Validators
 						}
 					}
 					$validationjs .= '} } } ';
+				} elseif ($field_value['validation'] && in_array($field_value['validation'], array('requiredfromgroup'))) {
+					$validationjs .= $field_value['validation'] . ': "' . $field_value['validationParam'] . '" ';
 				} else {
 					// remove last comma (not supported in IE7)
 					$validationjs = rtrim($validationjs, ' ,');
@@ -145,6 +147,10 @@ class Validators
 				$validationjs .= $prefix . $field_value['fieldId'] . ': { ';
 				$validationjs .= 'required: "' . tra('This field is required') . '" ';
 				$validationjs .= '}, ';
+			} elseif ($field_value['validationMessage'] && in_array($field_value['validation'], array('requiredfromgroup'))) {
+				$validationjs .= $prefix . $field_value['fieldId'] . ': { ';
+				$validationjs .= $field_value['validation'] . ': "' . tra($field_value['validationMessage']). '" ';
+				$validationjs .= '}, ';
 			}
 		}
 		$validationjs .= $custom_messages;

--- a/themes/mytheme/templates/form--edit-event.tpl
+++ b/themes/mytheme/templates/form--edit-event.tpl

-				<div class="col-4 user_selector presenter1">{$f_eventPresenterProfile1}</div>
-				<div class="col-4 user_selector presenter2">{$f_eventPresenterProfile2}</div>
-				<div class="col-4 user_selector presenter3">{$f_eventPresenterProfile3}</div>
+				<div class="col-4 user_selector presenter1 presentergroup">{$f_eventPresenterProfile1}</div>
+				<div class="col-4 user_selector presenter2 presentergroup">{$f_eventPresenterProfile2}</div>
+				<div class="col-4 user_selector presenter3 presentergroup">{$f_eventPresenterProfile3}</div>