Displaying a "filtered" list in multiple sites (SP 2010)

Question

I have a problem:

I have a custom list with about 4000 items that I need to divide to different sites depending on an attribute in a specific column. I also need to keep the version history and I need a »master« list, where all the items can be seen by a specific group. The lists on different sites should have the same columns.

The sites would be all in the same site collection.

More specifically: I have a list of items opened by different clients. I need to divide this big list into different sites, one for each client. They shouldn't be able to view/edit items opened by other clients, there is a group though that should have access to all of the items in a list (preferably the one that already exists).

What I already tried:

I tried making a globalized list and then including it as a filtered web part in a separate site. This kind of works, but if the user opens the item (view or edit) SP opens the »master« (non-filtered) list allowing the user to browse through the master list, which is not good.

I tried with a content query. This could work but I have a similar problem as above. And there is also a lot of styling required to display the list (editing ItemStyle.xsl etc).

I tried with the »restricted views« method I got from the web, which basically creates a document with specific permissions within a document library that acts as a view. This forces the user to use a specific view or get a permission denied message.

What I could try (I am asking for help before I do because maybe I am missing a simpler solution):

• I could try restricting and forcing specific views with jQuery and SPServices, I'm not sure if this is possible though.
• I could make a copy of the main list to n sites, remove the items that shouldn't be seen by specific groups and then merge these items into a big master list.
• I could create n folders inside the list, limit access to those folders to specific groups (with Site Permissions), but I would need to move all of the items into separate folders. I could do this with a workflow and then, with a bit of code, start the workflow on every item.
• I have just thought of something new: maybe I could create new lists in those sites and then merge them with the big list I already have?

Before I start copying the lists and merging them, is there any easier way to do this I might have missed? I've been at this for a couple of days now and am running out of time.

Any help will be appreciated!

Thank you for taking the time to read all this!

Answer 1

If the master list is for reading purposes only (and it did not sound like your master list needs to be a single list), why not just create separate lists for each of your clients, and create views that are made available on a page for your admin users. So you don't have a master list, but a dashboard-like page with all the views of your different lists. This way, you are free to style the different lists, and manage views and permissions easily of each list without impacting the others.

I assume the users of your master list does not need to work on multiple items from across different sources at any one instance. Even then, there could be ways around those.

However, if that is a requirement, you can also try and keep multiple lists that have workflows that replicate items/changes to a master list on add/edit/delete (which is your 4th option in your list).