We design a Service form,  (Request to Access ). By default the form doesn't have SLA.

Items on the form ( CRM, ERP, VM,...) 

We want when requesters change the item on the form, Add a SLA to each item automatically.

for example: 

1-when requesters change the item "CRM" - form SLA set to 2 hours.

2-when requesters change the item "ERP" - form SLA set to 5 hours.

3-when requesters change the item "VM" - form SLA set to 8Set hours.

and etc...