How do I get ConfigurationSetting from calling assembly?

I'm developing a server control for our intranet. This control is only going to be used in two applications on the server, but they must be separate.

It has been established that these 2 apps will use a specifically named key from their respective web.config's. I want the control to use that key regardless of which application it's being used on.

How can I get that key from the application?

I considered creating a config file for the control, but that would be more to maintain. We're using config files, because we don't want to use the registry anymore. So the registry's out.

for example

VB Code:

'In the app
Dim strConn As String = ConfigurationSettings.AppSettings.Item("EQDB")
 
'I want (in the control)
Dim strConn As String = [i]CallingApp[/i].ConfigurationSettings.AppSettings.Item("EQDB")

I could pass in the values I want directly from the app(s), but that would mean I would have to do that for every page in the app(s) that wanted to use the control. That would be a maintenance nightmare.

I'm developing for developers, so I want them to be able to use this control with as little hassle as possible.

Any ideas as to how to get this?