Balance more than 7 WAN's with balance 710

I recently bought a balance 710 to balance 7 DSL lines. The maximun speed that the ISP can provide is 15 Mbit so I have now 105 Mbits total. From now to the next 4 months I need 300 Mbits total. Is there any way to balance additional DSL lines without purchase two Balance 710?


The next model up is the Balance 1350 and it supports up to 13 WAN connections.