Custom block for concrete 5

We moved our webpage from concrete 5.6 to V8. In 5.6 we had a custom block that filtered downloadable documents based on their tags and the tags of the page they were in. In V8 we use a block called document library. It lists the documents based on tags. We now would like to customize this block or create a similar block that adds a filter which includes the tags on the peticular page the block is used. We use this block in a stack and the stack is then used in the product pages.
We use this block to filter downloadable documents on a product website.
I estimate this to be a simple job for someone with concrete 5 experience.
old webpage is here: ch.vectorcontrols.com, new webpage is here: c5.vectorcontrols.com