The nonprofit getting the AFI grant usually comes to you. They act as the trustee and custodian of the sub-accounts.
If it is not an AFI grant arrangement, the nonprofit wishing to offer the IDA looks for a bank.
I guess you could go out looking for a nonprofit partner, but your bank would not want to be in a position of funding all the costs and match.
_________________________
Societies that do not find work in and of itself "pleasing to God and requisite to Man," tend to be highly corrupt.