I thought I'd put some closure. I was able to figure it out.
I had to create something called an installscript which takes the form of a .vdf file.
The script itself looks like this.
"InstallScript"
{
"Run Process"
{
"OWL Installer"
{
"process 1" "%INSTALLDIR%\\Install\\ndi-runtime-4.5.1-Windows.exe"
"command 1" "/silent"
"NoCleanUp" "1"
}
}
}
A big help was looking at the vdf files of other games which also required an installscript, such as directx install, anti cheat software.