Best Process To Combine Drum Sound?

I produce electronic music and the kick drum is critical.  I've been thinking about melding 3 different sounds to create a combined kick and then routing the 3 tracks so that I can EQ and compress the combined sounds.  I'm thinking that routing the 3 tracks to either a new Aux Track or a new Patch Point is the way to go for this, but I haven't used this function much in my 20 years of using Cakewalk/Sonar.  What would you recommend would be the best process?  

You are correct in assuming that an aux track (or bus) is the way to sum the kick samples. That way, you're able to treat all three samples as one while mixing.
 
Just be aware that layering kicks can be trickier than you might expect, because the three samples need to be in phase with one another. That can be challenging because any three random kick samples will have three different fundamental frequencies. That's another reason for using a single instrument (e.g. Addictive Drums) for all the stacked samples, because they've already been phase-aligned for your convenience.

Yes, Laying down 3 separate audio tracks containing your selected tracks that you want to combine , and sending them to a summing aux track ,will make it easier to blend in the mix stage and adjust as opposed to having to go all the way back to the source vsti etc. to correct if it's not fitting like you think it should be (flexible that way, with less backtracking to correct) Imho.
Side note (all processing done on aux track simplifies)).   

I typically freeze the midi track data and drag it to 2 audio tracks.
I use drum replacer and fine tune phasing within DR (there is a setting to move the sample forward/backward). I then route my midi kick, my 2 samples to the Drum bus.
 
DP is worth looking at because you can use your own samples or some of the material that comes with DP.
The material that comes with DP is mutli-velocity (like an SFZ). Something you might run in to issues with if your using a 1 velocity audio sample.