UX and UI in different teams

I am looking to get some advice. My company are looking to split the UX designers and UI designers up. The UX designers would be sitting in their own team while the UI designers would be sitting in the marketing team.

I am in the process of trying to prove that this is a bad move as it will destabilise the process.

The process at the movement is UX and UI work together to create great solutions for the website. My main worry is that if these were split the priorities for each team would become different, making things less consistent and longer to produce.

Please could you help with any further reasons why UX and UI should always be in the same team?