Firewall ports

I back up a lot of my data on a computer on my home network.  To use passive FTP, you normally setup a block range of ports that are open for the ftp server to use, however, in the settings for the firewall, it appears that I can only map a block range of ports to a single port.  

Is there an advance setting to do block port range?  on my old asus router, I was able to open ports 50000-50100 and it would map to the internal computer on the same 50000-50100

Thanks