As Stuart suggested:
1. draw a marquee around the area you want to work in (thick for multiple storeys, light for one storey only)
if you have an element that runs through two or more marqueed areas the first person who signs in gets it.
This approach does not work when you need to (typically) work on zones or enclosure walls, facades, RCPs or any floor plan continuous area-like / perimeter-like elements.
It works for furniture, annotation, internal / partition walls or any local / self-contained areas in a sense.
Try to manage your work differently eg. different task based on layers - one person is annotating, second dealing with overall set-out, third placing furniture etc
In regards to Teamwork - it has got its shortcomings but I really do hate extensive hotlinking as it imposes question marks in several areas:
1. problems with workflow (eg. sections/elevations works can't be distributed among team mates)
2. portability (having more than two offices - different drive names and MS Windows whims)
3. there is always some smarty pants creating new attributes in linked file so you can end up with zillions of fills, layers etc in the master file (and I will laugh if someone tries to tell me that CAD manager can look after that - a mission impossible, sometimes I feel like they wait to create a new layer named 'Wall next to bedroom 2' with all possible elements in it just to see my dismay)
4. no automatic backup (TW file does have it - a quick fix solution without calling IT fello)
5. can not use Trace tool to full extent
and so on...
::rk