KUKA|prc allows file splitting, however you would still have to copy every file onto the controller, running into the same memory limitation.
In order to split it into completely separate files, take a look at the attached file. Of course it depends onto your process whether you can just stop and resume at some point.
To run files of any size, you could use KUKA.CNC (quite expensive) or external tools like OrangeTools Pointloader (which worked fine for colleagues and is not that expensive), or stream toolpaths via interfaces such as mxAutomation.
I would strongly recommend against playing with the memory settings on the KUKA to accommodate larger files, at least without having a proper backup.