Can You "overdub" Midi? Options

[bigsnack]

Greetings!

I'm a newb to the forum and to MIDI, but have been engineering on and off for years now. I am currently running ProTools LE 6.9 on a G4, and I have a quick MIDI question:

I am trying to use a MIDI keyboard/controller to record a stereo track of BFD for a demo. Prior to using the keyboard I simply wrote in all the MIDI notes manually. Anyway, I'm wondering if I can "overdub" MIDI, meaning can I take a 1st pass on my MIDI channel to record kick and snare, and then go back and "overdub" the hihat / cymbals on the same MIDI track without erasing the pass of kick and snare that I already recorded? Basically I'm hoping that I can use MIDI and BFD to operate very similarly to how an old school drum machine works. Any help or advice would be great, thanks!