This is not a dedicated link for one MLS Client. Many can connect to the Symposium server on the CLAN IP address Port 3000.
However, you want to be careful when registering more than one CTI server against the same PBX resource (DN, ACDN, CDN) to ensure you do not have applications competing for control of the resource.
Also suggest you upgrade to the latest SCCS SU PEP. There is a fix done over the last year or so that specifically addresses having more than one Third Party CTI application connected to the SCCS server. Any SU PEP from 6 months ago going forward will address the issue.
BTW, if you already have a Genesys T-Server performing call routing then you should be able to use the same T-Server plus desktop client to perform a screen pop. No extra server CTI is needed. But if your design goals require another CTI server then you can run another T-Server against the SCCS and use it for screen pop.