Being nice is my weakness!?

Whenever I see lonely kids I can't not feel bad for them, so I go sit beside them and such and be nice to them, and eventually we become friends. They arent like my other friends cause they are a bit awkward. I guess you could say socially inept. I was fine hanging with these kids at first, but now I have made too many friends for me to handle. Ibtry to combine the two groops ( awkward and my buds) but it just doesn't work. I just want to be able to go back to my old friends, but I feel awful when I ditch the awkwards. What should I do?