Though I can't certain, I guess it's possible.

First, there are no problem between BCB6 and BDS2006 basically, but you should pay attention to the PATH system environment variable.
To avoid the PATH confliction, I recommend you to make two batch files to run the each version which have SET PATH command before launch the C++ Builder.
If it does not work, just rename the folder name of the other version of C++Builder.

Registry and install path of C++ Builder is independent to each other. You don't need to pay attention to it.

Regards,
peperu

alex 님이 쓰신 글 :
: Currently we are having problems with running Builder 5 and Builder 2006 on the same PC. It just doesn’t work. Is it compatible?