Paradox, Referential Integrity, DbiDoRestructure, SQL

I want to create referential integrity (RI)
on Paradox files on-the-fly, from one master
file to more then one lookup file.

Using example in DbiDoRestructure, I can create RI
only on one lookup file, whichever it is. The attempt
to create second, third, etc. RI allways fails.

Is it possible to create RI with SQL, I can't find
any help in Local SQL Help.

I'm creating RI with no problems on Oracle DataBase.

Any help will be appreciated.

Thanx, Nenad