aptitude's analog to "apt-get ... -t"?

[Lloyd Zusman <ljz@asfast.com>]

I'm trying to figure out what, if anything, is aptitude's analog to
using the "-t" option with apt-get.

In other words ...

Given an /etc/apt/preferences file which prioritizes "stable",
"testing", and "unstable" distribtions, I can get apt-get to override
this default priority by using its "-t" flag.  For example, if my
/etc/apt/preferences file specifies that "testing" is the default
distribution (by giving it the highest priority), I can override this
and install a package from, say, the "unstable" distribution as follows:

  apt-get install -t unstable the-package-name

Sometimes I'd like to start up aptitude in its interactive mode and, in
a manner similar to using the "-t" flag with apt-get, have it perform
all of its package operations on one of the distributions which isn't my
default.  Does anyone know how I can make aptitude do this, short of
manually changing the priorities in /etc/apt/preferences before starting
aptitude?

Thanks in advance.

-- 
 Lloyd Zusman
 ljz@asfast.com