Yes Definitively , it will be difficult to have dedicated hardware so after more investigations , GNS3 is amazing and can do a bigger part of the job but need again to emulate this on the server so it is taking more resources. Take in mind that you can’t play with DSP so PRI connections and so on.

Think about 5 servers and a router Topology with at least 4 routers ( HQ, Branch 1, Branch 2, PSTN/CME). So it is becoming huge to maintain for hardware resources !!!