Ringtone question

I have a Storm and i have a question regarding ring tones. I enjoy giving all my contacts a special profile. (i.e their own ringtone for phone calls, texts, messages etc) However I have a few contacts that i could use several different ring tones for..I know they have an app that rotates randomly different ringtones as a default ringtone for your phone..is there an app that allows different folders for different contacts. Not sure i'm explaining this properly. Example Sister...ringtone is "alert your sister is calling" I also have a ringtone of one of our favorite songs..and i also have a ringtone made of her singing..instead of having to physically go into her profile and changing the ringtone for her...could an app possibly assign her a folder and i could put all of the ringtones that i want associated with her in that folder..? so i could randomly hear one of the ringtones from that folder?

Just wondering if this can be done or maybe is already done..