I have a new install for a client consisting of an SPA 9000 and 2 SPA 400s. One of the SPA 400's is for 4 PSTN lines and the other is for voicemail. No VOIP providers are involved. The client has a total of 6 employees. They currently have a key system that is setup to have one PSTN number the inocming line and the others the outgoing lines. Can I configure this on one SPA 400? Or would I need to use 2 and setup an incoming call route on line 1 of the 9000 and an outgoing route on line 2 of the 9000? Any help would be appreciated. Thank you.