Hello and welcome to the forums,
What's you're asking for is possible and quite easy to achieve. It will, however, require some coding. It's best to start with your own new module, you can get instructions on how to do that here:
http://www.epesi.org/index.php?title=Cr ... dule_files
After the module files are ready, you will need to use method:
Utils_RecordBrowserCommon::new_addon('tasl', 'Your/Module/Name/And/Path', 'method_name_to be_created_in_main_file', 'Phonecalls');
From there, create appropriate function in the main file of the module. This method accepts one argument - the record under which the addon is being displayed. You should use that record, take customers field value (it'll be an array) and apply it in crits to display selected phonecalls.
I recommend looking up Premium/Projects/Tickets code for hints on how to initialize and use RB in addons, here's the code:
public function premium_tickets_attachment_addon($arg){
$a = $this->init_module('Utils/Attachment',array('premium_tickets/'.$arg['id']));
$a->set_view_func(array('Premium_Projects_TicketsCommon','search_format'),array($arg['id']));
$a->enable_watchdog('premium_tickets',$arg['id']);
$a->additional_header('Ticket: '.$arg['title']);
$this->display_module($a);
load_js($this->get_module_dir().'/screenshot.js');
Base_ActionBarCommon::add('add', 'Attach Screenshot', 'href="javascript:void(0)" onClick="ticket_attach_screenshot('.$arg['id'].')"');
}
I apologize that addons are not covered on our wiki, we're looking forward to fix this and other issues with documentation in nearby future.
Kind regards,
Arek