How to add a default route on Zabbix namespace on Zabbix resource restart

We are using Zabbix plugin on Mirantis OpenStack 10.0 to monitor the stack. To enable email notification, it needs to add a default on Zabbix namespace. Manually adding a default route in zabbix namespace on the controller node where crm resource 'p_zabbix-server' is running, works. However, we would like to automate adding the default route on crm 'p_zabbix-server' resource restart.

I was wondering which configuration file that I could leverage to make it happen. Thanks in advance.