You can do this, however each server has to manage their own JTS and licensing.  You won't be able to share code changes across RTC repositories (distributed SCM).   And if you extended it to lots of separate JTS servers you would also find that each user (say a tester or developer) who needs to work across multiple JTS servers in RTC would have to have multiple licenses assigned to that user to perform "save" operations on multiple servers.   So for example if you had 3 JTS servers JTSA, JTSB and JTSC and a tester "Ian" who needs to edit work items in all 3 servers then Ian would need 3 licenses in each JTS A, B and C allocated to him.  

In RTC 4.0 we also have a new RTC Developer for Workgroups Starter Pack which will also give you 24x7 support for your "10 free" licenses so this might be something to look at as well as it can be combined with other licenses on the same JTS and the entire JTS would have 24x7 support, so you could have ONE Starter Pack on each JTS and then add say an RQM licenses to each.   (and it's cost effective, with US list at $600/user for a perpetual license, or term licenses at less then $25/user/month with an annual contract).  Note that the Starter Pack (like the 10 free) can only have one linstalled per licensed server group (usually per JTS server).