// get the current user id and then get the company name associated with user
$user_id = get_current_user();
$company = get_field('company_name', 'user_'.$user_id);
// get a list of user IDs associated with the above company name
$args = array(
'meta_key' => 'company_name,
'meta_value ' => $company,
'fields' => 'ID'
)
$users = new WP_User_query($args);
I’m not sure how the posts you want to get relate to the list of user IDs
