At this moment one is not able to change the name of the connection string, so it is not possible to have several connection strings within the machine.config file. We are discussing adding configuration variable for the name of the used connection string in future versions of the product(probably for the Q3
Proper solution to your problem is to simply change sitefinity's backend permissions, so one to be not able to access 'Administration -> Files
' and/or 'Administration -> Settings under Data -> Connection Strings
', whether you are storing the connection string in the web.config file or in the DataConfig.config file.
On my opinion is much more easier/effective to put the connection string in the web.config and then to change the permission of the Files
page. You just need to open 'Administration -> Backend pages
', to find the Files
page, to click on the 'Actions -> Permissions
' and finally to configure the needed permissions properly(probably you will need to configure only the page's view permissions).
the Telerik team