Logback - spring property - substring / replace

Question

So the case is ultra simple in theory - harder to get it working in real life. I have a property:

my.loggger.test.property=file://some/path/to/log.log

I define it with such pattern in logback.xml and everything is working as expected:

<springProperty name="filePath" source="my.loggger.test.property"/>

Case is that I want to (without editing application.properties) substring / replace some characters on it so I would love to have something like:

filePath = filePath.subString(5) 

or

filePath = filePath.replace("file:/", "")

Is this even possible ? I cannot find any information about string manipulation on logback.xml.