manage source control when clients can add to it within CI environment

I am after some advice / guidance on how to deal with a source control issue. Historically we have everything under SVN in the one dev branch and a release branch. We have one section that contains a lot of the content files as well as images and CSS files. We do make changes to the files in these folders sometimes, normally the CSS files. Our client also has access to these files as they do part of their CSS and general content management them selves.

We have now taken this folder out of the main dev branch and moved it into its own "开发者_StackOverflow社区resource" branch. This has taken it from over 3GB to under 1GB in the dev branch.

We are in the process of setting up TeamCity and getting as much as possible automated. Our issue is how best to deal with the clients making changes and pulling them back down into our dev enviornment, also how to push our changes up without conflicting with their changes. Obviously this can be done manually but we want to get away from this time consuming model and automate as much as possible.

We are happy to except that we can make the assumption that the clients changes take precedent over ours. I have got as far (in thinking about it, not implementation), to say that we have another branch "dev-resources" and we do a nightly pull from the clients resources branch and merge them together. Not 100% sure what the best way to automate this is, for example conflicts, making it choose theirs and then flagging this up so we know there was an issue, or getting it to fail at the point of a conflict.

The next issue is how to push our changes up to the clients resources branch.

I cannot see any process that would be fully automated due to conflict issues but if we can automate 90% and can make it visible when there is an issue that would be great.

Thanks