It's probably possible to call any EXE from a Director project. You could probably also pass some information along via the command line. However, once the Blitz-made EXE is running, it wouldn't be possible for any direct communication between the Director project and Blitz application. On the other hand, you could always write data to a data file to exchange information. Don't know what you're trying to do though---this might not be fast enough for your needs--or maybe you don't need 2-way communication at all...?
Also, this method means that the Blitz-made EXE would not be embedded, but rather a secondary file. It is possible, using a file packer like MoleBox, to embed the Blitz EXE within a Director-made EXE.
Also, this method means that the Blitz-made EXE would not be embedded, but rather a secondary file. It is possible, using a file packer like MoleBox, to embed the Blitz EXE within a Director-made EXE.