Midi "router"? Options

[Turner]

Hi all -

I'm using GarageBand as my main app here -

Just wondering if anyone knows of a MIDI-router-type thing... not sure exactly what it would be called, but as an example, I'd like a pre-GB software device which can take my MIDI input and reroute it, the same way you might assign pads to a MIDI Drum set (one of the things I'll be using..)

So, you might have a signal coming in on, say, middle C - I'd like to be able to say, "ok, make that a middle A".. and so forth.

Even better would be if I could split that, so middle C might become 5 different notes at a time...

And even better would be if parameters could be set, too, so that if you had input below a certain velocity, for example, it would be set to a given velocity, say, any velocity below 40 simply becomes 40.

Any leads?

thx
Andrew