Validation to Require Linked Ticket from Certain Project

[Justi Lawson]

I am working in Jira cloud and looking for a jira expression validation that will require a ticket to have a linked issue to a certain project if a custom field is yes. 

I do have script runner for cloud.

field = yes/no

For example, 

if field == yes then require linked ticket to project('xyz') 

else (if no) let the ticket transition to next step.