How do I allow a field to be populated dynamically on Gravity Forms using URL query strings to redirect it to a CRM?

I am using a drop-down menu on Gravity Forms with 3 items:

a. Alpha b. Beta c. Theta

I need the selected drop-down information (one of the above three) to redirect to my CRM. Since it is a drop-down, the values will have to be populated dynamically and sent to the CRM or.

These are the drop-down menu's details: ID: 4 Admin Field Label (name): interest Dynamic Parameter Name: value

And this is the form field mapping name on the CRM server for the 'interest' field: interestcrm

Now I use query string to send the information from the field on my Gravity Form to the CRM.

This is the current query string for the drop-down menu: "interestcrm={interest:4}"

This is a sample format of how a longer query string will look: 'interestcrm={interest:4}&phone={phone:2}&message={message:5}'

So now how do I add the dynamic parameter name (value) to the above query string?

I tried 'interestcrm={interest:4=value}' and it did not work and the other answers here don't talk about mapping them. I prefer not to go into php or js but will do if really necessary.

Please help me out here.

Thanks in advance.