Can I require to satisify multiple conditions based on spf record

If I have spf record "v=spf1 ip4:192.168.0.0/16 ptr -all" that would mean 
its either 192.168.0.0/16 OR mail server with the domaini in reverse.
But lets I want SPF record that says mail that comes from example.com 
domain MUST come from ip range 192.168.0.0/16 AND IT MUST come from mail 
server that has PTR that domain. Can I enter this within SPF record? How?

-- 
William Leibzon
Elan Networks
william(_at_)elan(_dot_)net