Can you elaborate more on the "System Settings" you are referring to.
The link control can accept links those have the protocols "Http, https, ftp and news", Though it provide the "Other" as protocol, Let us say if we try to use "file" protocol then it may not work as per the security established between the browser that trying to access the local file and the operating system it is on.
So, in the system setting you are referring to, what is the protocol of the URL or the way you try to access the setting.
So, if you can try to explain the requirement you are trying to achieve then it would be much easier to imagine the problem to help you further.
Please feel free to reply if you have any further questions.
I get the problem you are looking for. You are trying to refer a DSS setting where the key remains same but value becomes updates with specific to that environment. If that works follow the below approach
1) Create a property that hold the URL from DSS value (Please make sure to run an activity to pull the value from DSS and updates the property with "property-set" method)
2) Create a section and configure the link control in the section
3) While configuring link control, use the "Property Reference" and refer the property that created in Step 1.
4) In the paragraph rule, click on "Insert Rule" Icon then select "Rule-HTML-Section" and refer the section created in Step 2
At runtime, the link will be rendered with a source link to the value of DSS. As you update the value in DSS key for each environment, the paragraph rule picks up the value from DSS value.