Hi Fireflight,
Have you tried engaging the screaming lady? Maybe giving her something useful to do, such as folding newsletters or other papers, filing random papers in manilla folders, something so she feels like you need her help.
Have you talked to her or her family to get an idea of her interests? For example if she was passionate about gardening, give her dirt and pots, seeds, etc.
As far as the other people in the group, maybe some activities that don't take a lot of explanation: puzzles, coloring, sorting playing cards, folding towels.
Hope these ideas help!
Tricia