SQL Server 2012 Standard Clustering - multiple instances

Hi,

We have an existing 2-node Windows 2012 WSFC running SQL. The current instance is a default MSSQLSERVER one. The WSFC has 5 volumes:

Quorum (Witness Disk)
SQL Backups
SQL DB files
SQL log files
TempDB

If we installed another clustered SQL instance to this WSFC, I'm assuming we'll need another 4 volumes (as above excluding the Quorum as that is for the WSFC itself), because multiple clustered SQL instances cannot share the same disks like you can with standalone multiple SQL instances?

Thanks