transparent highlight effect

[Nicolas Cueto]

My apologies if this is out of place here.

An example of the effect I'm after can be seen
on the "treasure hunt" game at:

http://www.bbc.co.uk/skillswise/words/grammar/interestsentences/pronouns/flash0.shtml

Basically, at its treasure hunt level the game
shows a map overlayed by a 14x7 grid of
1x1 cm squares, each of which becomes
transparently highlighted when the mouse
pointer is within it (and, when not, returns
to its original state).

It is that "trasparently highlighted while
mouse is within" effect that I'm after.

But, the only Rev option I know for this
is blendlevel -- and that would be a
painful solution, cause it'd mean having
to first draw the 81 interlocking pieces of
the map (ouch!), so that they could then
be imported into a stack as image objects,
the only Rev object on which  "blendlevel"
has an effect (right?).

Is there an easier way?

Thanks for listening.

--
Nicolas Cueto