I currently have an R4 in Raid 10 that is running out of space. I want to expand capacity by purchasing another physical array, probably an R6 this time.

Is there a way to get these two seperate arrays to show up as a single volume on my compute WITHOUT having to reformat them? Basically I would want to combine these two drives so that they act as one logical drive on my computer, but I don't want to have to backup and then reload all of my data. 

Follow up question: If this is possible, can it also be done with different Raid levels, for example keeping the current one in Raid 10, but formatting the new in Raid 5, but still have it show up as one logical drive?