Hello Avril62,
You could set up each grant as a 'bank account', you could then enter an opening balance of the amount remaining of the grant and use these accounts to pay your bills, depending on which grant you are using to pay that specific bill. You can do this by going to accounting, then chart accounts and set them all up as 'cash at bank and in hand'. We would advise it would be best to speak to an accountant about this though, to make sure they are happy on how you set this up - as it may have to involve journal entries to ensure you are recording this correctly.
Thanks,
Talia