Application Role within Approval Groups

Summary

Application Role within Approval Groups

Content

Hi,

Any idea why the option 'Application Role' is not allowed for selection from the drop down list while creating an Approval Group ?? I can only add users or another approval group but can't select this Application role option. 

I read another blog that there was an ER for this purpose # 25090414 but could not found that information either.

Please let me know.

Thanks,

Sree