Can I pass in a value to a registration custom question via URL?

[boyermichael942]

In the Registration Settings, I set up a required custom question as a single answer drop down.

Let's say, I'm asking for registrants to select Dept within a list of Dept1, Dept2, Dept3, Dept4 during the registration process.  

Is there a way for me to pass in a "Default" Dept value via the Webinar Registration Link.   For example, if I'm inviting everyone in my email list that works in Dept2, I want to send them the URL link such that when they click on it, "Dept2" is already selected or populated but could still be changed if they needed to change it.

I was thinking I could pass in the value of Dept Variable, but can't seem to figure out how to do it.    Thanks in Advance.