Every Company will have its Silos, some more siloed than others. Some departments/functions are more siloed than others by virtue of the work they, for example if you look at some of what I call back-end functions such as Technical Operations or Industrial Operations, alot of thier activities are withing function, think Quality for example, where the cross-functionality will come it say when they are planning stability test for a regulatory purpose or a commerical purpose, but when new data-emerges that may Impact the dossier (i.e. shelf-life or storage) that Impacts both regulatory, Commercial drug supply, right? So you can have a subset of activities that are cross-fuctionanl that are planned (strategy) or reactive (put out a fire). But most of thier work is withing function, day to day "silo" operations, contrast cross-function work.
Then you go the other extreme and you have functions that depend on cross-fucntional work, take Marketing. It's an integrating function, that integrates activities other functions into an actionable cross-fuctional strategy. That's a key Task of what Marketing does, it HAS to move accorss Silos to get the Expertise they Need to have an integrated and aligned strategy with cross-functional Investment/tactics. So that's the extreme. More cross-function work than withing function work.
There are many Drivers of Silos thinking, one is that you Need some Silos, i.e. you Need ot rely on interal expertise, seriously, you don't Need a Marketing guy knowing everything a Quality guy is doing right? that's insane. But you should know what theier competency and key functions are as it relates to your brand. Then there is, one doesn't know what they are doing has cross-fuctional relevance. And example here is a Quality and Regulatory person not reporting a dossier impacting stablity issue resultig in shelf-life changes that will drug-supply, artwork Management, Commercial competitiveness etc. Then you have politcs.
So your Dilemma, I can say breaking down Silos, and doing what I call bringing transparency cross-fucntionally, is usually always a win! And this where I've gotten some huge wins and not to mention visablity. Holding the view that you should hide Information is well - politics and you can get hit negatively.
However, you can control "how" that Information is "communicated'. You may be sitting an opportunity to help that department/function. They will never be able to replace your function right? you have a role and Job to do. You could asked them how you can help. You could suggest you lead a "Task force" or a "Workshop" to understand Needs, and snap an Action plan. Set Goals. You could be the Agent of empowerment - you can offer yourself up as their subject matter Expert (SME). And I bet you'll see Information will start to flow both directions and you may even break down politics - you may find root causes and some maybe de-myth some perceptions Held by others. And this is why you'll others may consider Marketing as a leading function right?
So my recommendation, see what you can do to Support them - bring the key stakeholders in to a Meeting. Involve your Supervisor. You can set up a lunch and learn between your two departments. These are some of the Tools I used. You can run a quick Workshop, define key question,and define an Action plan. I bet you find they don't want ALL your knowledge just the relevant Points to do the work they do. (see my Point on "how" that Information is "communicated", you're still in control).
Take the lead! You WANT to be the tranparent guy, you DO NOT want to be the hidder. I've never lossed by being transparent - i'e called a spade a spade and an ace and ace and that was my big win my last year's Performance Review. I broke down a few Silos and brought transparency in ways that was not done for my Brand before.
So go to it, aling with your managment and plot a course forward.