To do record level validation, you can use the CurrentRecordContextChanged event. Here is code that will not let you leave a record if Col1 has a 1 in it.
private void gridGroupingControl1_CurrentRecordContextChange(object sender, Syncfusion.Grouping.CurrentRecordContextChangeEventArgs e)
{
if(e.Action == CurrentRecordAction.LeaveRecordCalled)
{
GridRecord record = e.Record as GridRecord;
if(record != null && record.GetValue("Col1").Equals("1"))
{
e.Cancel = true;
}
}
}