You could have a small VI which contains a duplicate of the control in the other VI. The small VI runs, gets the value of the control and saves it to a file which can be read later by the main VI to set the control using property nodes.
I am not clear on what you mean by not running the main code. Something has to be running to do anything in LV.
Depending on what is running, you might be able to do something with VI server as well.
Post a more detailed description of what you are trying to do and someone will probably be able to help.
Lynn