Oracle Designer 6i : multideveloper project

[OscarI]

I have a problem with organizing a multideveloper project
with Oracle designer 6i.

Given :
Oracle designer 6i with repository set up for versionizing


I have two developers A and B with their own private Workarea. A and B should develop entity relationship diagrams which have a relationships between
each other.

How could that relationship be realized ?
1. Directly form ER of A to ER of B?
2. Via the checked in versions of each both developers?
3. Via the shared workareas ?

I would appreciate hints for practical solutions ?

Many thanks in advance .

Oskar