Data Pump and db links

The environment I work here with heavily relies on db links due to integration efforts. At the same time we create numerous test/dev environments for projects' needs. Usually for test/dev environment we are not able to provide all the connections or data, while trying to provide 1 to 1 metadata structure. Of course part of it becomes INVALID, but that is ok. The point is to do an import at the lowest cost (in terms of time and writing), thus keep with a good principle, the IT staff should be lazy. The problem is that during Data Pump imports the worker hangs on views built upon non-existing db links, possibly due to firewalling connections.

1. one may exclude schemas with db link (EXCLUDE=SCHEMA:" IN ('[username]')"
2. one may define TNS aliases - in our case due to firewalls there was a need to indicate true databases (no matter that there was no proper schemas on them)