use IPC::Open3 qw( open3 );

local *TO_CHLD;
local *PIPE;
local *FR_CHLD;

my $com1_pid = open3(*TO_CHLD, *PIPE,      '>STDERR', 'com1');
my $com2_pid = open3('<PIPE',  '*FR_CHLD', '>STDERR', 'com2');

...

waitpid($com1_pid, 0);  # $? is com1_pid's status
waitpid($com2_pid, 0);  # $? is com2_pid's status