Call GetRequest while WebUI Test and extract a part of a XML-File while doing so

Hello!

While I am a rather development orientated tester, I am new to katalon and I have to fulfill a difficult quest:
For a registration form, I need a new IBAN every run. I have one page/Request which gives me an IBAN which the backend logic accepts (most IBAN-generators fail here, don´t ask me why). So i HAVE to use that page for now.

So I do a GET Request on ᐅ Germany / Deutschland Fake Name | Address | Credit Card | Generator on postman, which (whatever you determine as acceptContent, it delivers an XML, where i have to extract what I need with postman and cheerio:

I already created the endpoint Test in Katalon, but I am not able to withdraw the text I need (the IBAN) from the xml I get. Can anyone give me a hint maybe? What would be your best take on the problem?

(And yes, I know: This is no good coding style or whatever I am doing here. There would be way easier API´s who just deliver an IBAN with way less stress - I tried a LOT of them, and no one of them made it through our verificationLogic. So for now, I have to use the data which I get from the endpoint mentioned above)

https://docs.groovy-lang.org/latest/html/api/groovy/util/XmlSlurper.html