How to validate Linked Issue name type based another custom field value?

[Teja]

Hi,

I have custom field named Cause (select type of single choice) and values Technical, Product and Other.

Now I need a validation that, when user selects 'Cause' field of 'Product' and force user to select Linked Issues of 'is caused by' value and issues.

How to do that on create screen? Any validations, I tried Validation on Linked Issues but did not work.

Any help would be appreciated.

Thanks