Doing it that way would be very difficult; as PP have said, getting out of the "family contribution" rule is very difficult these days.
However, claiming her as a tax dependent cannot help, no matter what the situation is. If she is living with a different branch of the family, then presumably that household is supporting her, not yours.
While NOT claiming her as a dependent probably won't make a legal difference in terms of her actual residency status, claiming her as a dependent is pretty much guaranteed to shoot down any appeal that she might make re: add'l financial aid on the grounds of what is known as "parental refusal." If she is granted a parental refusal exception her own income will be what is taken into account for loan qualification, but it doesn't qualify the applicant for Federal grant money -- no Pell grants.
(I understand that you are claiming that you cannot afford to give her financial support, not that you simply don't want to, but in legal terms it is the same thing: if she will look for adjusted aid eligibility because you don't support her, it really doesn't matter why not.)
I know a couple kids whose parents won't give them anything for school and their schools didn't have anything called a parental refusal
They were just told their aid was according to their parents fafsa and that was all they qualified for whether their parents gave them anything or not. So don't count on this adjusted eligibility.