Adding a single person to multiple groups at the same time

It would be nice to have a combo box for ctrl+clicking multiple groups for a single person in Users > Enrolled Users > "" icon for adding groups. (Now it is a pull-down list that allows one choice only, I have to choose one group, click submit, go back to the Enrolled Users, click the "" icon again, and get back to the pull-down list to add the same person to another group.)

You may wonder why I don't add individuals in "Groups". Actually I have added the individuals to each of Groups A, B, C and D. Now all people in groups A and B belongs to Group E, Group F=B+C+D, Group G=A+B+C, Group H=B+C. So I don't want to add people to Group E, F, G and H group by group.

The reason why I cannot use grouping is News Forum needs groups not groupings. Actually I have made groupings accordingly for the other functions.

I cannot simply send emails to the groupings because I am still adding people to individual groups and I am afraid I may forget who has received the email and who has not. I hope to put the message in the News Forum such that the newly added people can also read it.

I hope I am clear enough of my need. It would be very helpful if the said function can be included in the future upgrades.

Thank you very much.