Adding new disks to SQL 2012 AlwaysOn Nodes

I am having a bit of an issue with adding 2 new disks to a 2 node SQL 2012 Always On setup.  I am currently running 2x Windows server 2012 R2 Datacenter VM's with SQL 2012 Enterprise with SP2 installed.  SQL AlwaysOn is already configure and functioning properly (maybe?).

I am trying to add 2 new disks to the existing SQL AlwaysOn Nodes.  I can successfully add disks to Node 1 and assign them drive letters.  But when I go to Node 2 and add the disks, I can't assign the same drive letters as what was assigned on Node 1.  I suspect that Windows Clustering is coming in to play here.  Is there any way to add disks to each node with the same drive letters on each node?

Thanks in advance.