Change the location of Confluence page based on Jira project

[AtlassianAdmin]

We have a script runner post function that create a Confluence page and links it to the triggering Jira issue. However, now we want to check the project in which Jira ticket is created and create Confluence page in a different location. Basically use different ParentPageID for tickets created in different project. 

Here is the code that I tried but isn't working. 
def projectname = underlyingIssue?.getProjectObject()
if (projectname == "OTP") {
def parentPageId = "2082177064"
}
else {
def parentPageId = "2055077911"
}

My question - How do I identify project key of the issue in question? 2) Is this how location of Confluence Page creation be differed. 

[Peter-Dave Sheehan]

In a behaviour, you will only have "underlyingIssue" after the issue is fully created. During create

I'd recommend you refer to "issueContext" instead if you need the project key. This will always work.

def projectKey = issueContext.projectObject.key