Where & How can i user logon groups which i create under /nwa link
under SYSTEM MANAGEMENT --> CONFIGURATION -> LOGON GROUPS
Logon load balancing increases the efficiency of various work groups. To improve performance and system resource consumption, users are distributed across the available application servers based on the requirements of work group services and load sensitivity. Eah SAP application has different resource requirements, therefore certain applications that may require more servers and logon groups can be created and configured in this view.