A RAID-like 2 SSDs after install just not to waste space

Hello guys,

I have a PC (yes, A PC) running OS X mavericks and I have one question.

I Couldn't install on raid0 with 2 SSDs so, now I'm with 2 SSDs separated and I only have 64GB for my OS and apps, and another 64GB free space.

So, my question is: Is there any possibility, to use other drive to share space with the "main" drive? Like putting it half of apps I WILL install? Choosing the path etc etc?

I thought about creating symbolic links on Application's folder to the other SSD.
It will result?

And how about external HDD on rMBP? I have on my rMBP 256GB ssd so it is enough for me, but I'm wondering if is possible.

I'm trusting on unix power, everything is possible

A great trick is doing links. I tested and It works.
exFAT (external partition of a HDD) I added Firefox.app there in a folder (Programas MAC , stands for MAC Programs in english).
then, I created a symbolic link to the .app folder.


It automatically shows the firefox on launchpad.
but, some programs that cleans stuff, for example: AppCleaner, it won't show links. It won't follow to the drive. It just ignores.