@sumbuddy, yes it can be done using a env file. I am doing it for 10 versions of NX (NX4 to NX7, All the NX7.5s and NX8).
I set the system environment variable UGII_ENV_FILE to point at my env file.
Then in that ENV file I set all the common variables at the start, then I test for the version of NX you have started, by using either the variable UGII_VERSION or UGII_FULL_VERSION, see below for what I mean:
#########################################################################################
########## NX6 ############################################################
#########################################################################################
#if $UGII_VERSION = "v6"
UGII_BASE_DIR=c:\eng_apps\nx6.0.5.3
UGII_ROOT_DIR=${UGII_ROOT_DIR}\UGII\
UGII_USER_PROFILE_DIR=${AMG_CUSTOM_DIR}\nx_v6\user
UGII_USER_DIR=${AMG_CUSTOM_DIR}\nx_v6\user
UGII_SITE_DIR=${AMG_CUSTOM_DIR}\nx_v6\site
#if FILE ${UGII_BASE_DIR}\ugii\ugii_env.dat
#include ${UGII_BASE_DIR}\ugii\ugii_env.dat
#endif
#endif
#########################################################################################
########## NX7.5.0 ############################################################
#########################################################################################
#if $UGII_FULL_VERSION = "v7.5.0.32"
UGII_BASE_DIR=c:\eng_apps\nx7.5.0.32
UGII_ROOT_DIR=${UGII_ROOT_DIR}\UGII\
UGII_USER_PROFILE_DIR=${AMG_CUSTOM_DIR}\nx_v7.5\user
UGII_USER_DIR=${AMG_CUSTOM_DIR}\nx_v7.5\user
UGII_SITE_DIR=${AMG_CUSTOM_DIR}\nx_v7.5\site
#if FILE ${UGII_BASE_DIR}\ugii\ugii_env_ug.dat
#include ${UGII_BASE_DIR}\ugii\ugii_env_ug.dat
#endif
#endif
You will see that I set the BASE & ROOT DIR and other dirs. The most important thing is at the end to include the standard NX env file (ugii_env.dat for NX6 and ugii_env_ug.dat for NX7 and above).
I used to advocate the bat file method, but I have been testing this for the last 2 weeks and rather like the fact it's one file for all the versions I run.
Anthony Galante
Technical Resource Coordinator

NX4.0.4MP10, NX5.0.0->5.0.6, NX6.0.0->NX6.0.5, NX7.0.0->NX7.0.1 & NX7.5.0.32-> NX7.5.4.4, Beta NX8.0.0.25