Are you familiar with APIs?
I am attaching the API I made, you just have to change the txt file to .BAS and you can run it from Femap.
It will prompt you to specify a file name that will create a txt file. Then it will prompt you to select any number of groups. If those groups have nodes in them, it will write SET1 cards for each of the groups selected, to that txt file. From there you can copy and paste those into your input file.
Now I just made a minor revision to something I already had. So I can't guarantee that it's perfect so please test this. And if this doesn't fit your workflow, please let me know and I will try to change it to better suit you.