Dear Louise,
You can create a new codeset (e.g. "Sources") with one child code for each of your source databases. Next, in the sources tab on the right of the screen (click Sources at the bottom of the area where your codesets are normally displayed), click the List button next to each of your source databases. This will bring up all the items from that database.
Select these items (by clicking the checkbox at the top of the list), and assign them to the relevant child code (by right-clicking on the code and selecting Assign selected items to this code).
Once this is done, all the items from each of your databases should be assigned a specific code according to which database or source it came from. You can then use this coding to allocate the work...
Click on the Collaborate tab, then the Create New button, and assign the items to the relevant person according to their source coding...
Hopefully this will allow accomplish what you wish to do!
Please let us know if not, or if you require any further assistance or information.
Kind regards,
Zak