How to add UTM (query string) to landing page url in ELQ - editor

Am I missing something or there is just no simple option to add some query string to Landing Page URL address in Eloqua Editor?

Using Vanity URL field there is an error while adding anything like: ....com/?LP=1

I tried several codes for JAVA and Tracking section but no results as well. And I need it for my forms that will be added to different LPs and I want to use query string in hidden field to collect them.

Any idea from you community how to add such string to LP URL address?