Best way to set host key in Modular Inputs

I am building a Modular Input but would like to set the host behind the scene. I know that I can use Scheme Default but that sets the default for all stanza.

[poll://Server1]
port=4532
comString=helloworld
id=1.23.22.15.3
#I want the value of poll to automagicly set value for host when the user goes through the Manager.
host=Server1

I know I could use a transform to set the Server1 host value during indexing, but there is got to be a better way with modular inputs. I don't want the user to retype Server1 Manager screen.

How would I accomplish this with the <manager>.xml, in a introspection, or in my .py script?