How to use non-global macros from other projects?

[Rogier]

I would like to have one "init_passwords.bld" project which sets some password macros, and then run that bld from several other projects. However I don't want to set them as global macros or environment variables. This way I can store all passwords at one secure place (the init_passwords.bld would be on an encrypted drive).

But when I use temporary macros, the calling project doesn't have access to them, and when I use project macros, it asks whether I want to save the bld every time.

So, I want:
- myproject.bld to run (or call, or include, or whatever) some init.bld
- init.bld to set some password macros, but not as global macros or env vars (at least not env vars that survive beyond myproject.bld's execution)
- use the macros set by init.bld in myproject.bld

I guess if projects could include other projects, rather than just running them in a separate session, that would solve my problem, and it'd allow for quite some other handy tricks as well.

Is something like this possible?