No, a mobile telephone number can only be used as a forwarding number on one Google Voice account. This is so that Google Voice can route inbound and outbound text messages between the GV number and the mobile number.
If you don't care about using text messages on the GV accounts, you can change the phone type parameter from "mobile" to "work" or "home" on both GV accounts. A landline phone number can be used on a maximum of two GV accounts.