Datagroup into variable

I think this question answers what you need to do:

https://devcentral.f5.com/s/feed/0D51T00006i7ebKSAQ

he uses a foreach loop with the datagroup as the variables then you put your command set url, and whatever else after that.

In this example, you have a datagroup called 'domains' and a record, 'mydomain.com' which has a value of '10.1.1.1'

 ltm data-group internal domains {
        records {
            mydomain.com {
                data 10.1.1.1
            }
        }
        type string
    }

In an iRule, you can use the -value switch to return the value in a datagroup, rather than a Boolean match when using the class command

The following code will set a variable 'url' to '10.1.1.1'

set url [class match -value "mydomain.com" equals "domains"]