Do you perhaps just want a list of Linux hosts and IPs?
Unless they are all running open SNMP or telnet ports there is no way I know of that you could list them and even then you'd still have to scan all IPs. The best way to start would be to find out the subnets used at your company so you can at least eliminate all the other subnets in the world.
Also it is possible that your company restricts all Linux hosts to a single subnet/vlan. Talking to your network admin may help. At my company we have a vlan for Windows, a separate vlan for Linux, one for Unix and yet another for dmz servers (which may be Windows, Linux or Unix).