It depend what you want to do exactly.
I imagine you want to install several apps by default and when it's done give the user the option to install a few others.
It could be done in 2 way.
If it's linked with an unattended CD, you could launch wihu a 1st time at T-13 using cmdlines.txt and a second time at the 1st final boot via [GuiRunOnce] in winnt.sif
You could use 2 different ini file if needed.
If it's not linked with an unattended CD, just create a batch file ex:test.cmd with 2 lines
CODE
wihu
wihu
You could also set different parameters for each wihu execution:
CODE
wihu /SkipSettings /INI=file1.ini /Autoinstall=5 /SkipRestart /Log=log1.txt
wihu /INI=file2.ini /Log=log2.txt
That's just an idea, but could work fine