We do not currently support this. If Ottimate considers the vendors the same, it will send a single check payment to the vendor and include the invoice numbers on the check stub. You could potentially add multiple account numbers so they all appear on the check stub, but we would not be able to tell the vendor which bill is connected to which account number.
A workaround is to create your own vendors in Ottimate, for example Verizon 123456 where 123456 is your account number. You would then need to edit invoices coming from that vendor and change to the appropriate custom vendor with your account number.