  We demonstrate the relation between critical temperature $T_{\rm c}$ and
transport properties in $R$FeP$_{1-x}$As$_x$O$_{0.9}$F$_{0.1}$ ($R$=La, Pr and
Nd). $T_{\rm c}$ and resistivity power-law exponent $n$ form a universal line
on the $T_{\rm c}$ vs. $n$ plane for all the $R$-systems with $x$$<0.6\sim$0.8,
indicating that $T_{\rm c}$ increases with bosonic fluctuation. Transport
properties show anomalies suggesting a change of Fermi surfaces around
$x$=0.6$\sim$0.8. Above $x$=0.6$\sim$0.8, $T_{\rm c}$ and $n$ approach the
second $T_{\rm c}$-$n$ line for the higher $T_{\rm c}$ systems. A further
increase of $T_{\rm c}$ above $x$=0.6$\sim$0.8 indicates the presence of an
additional $T_{\rm c}$-rising mechanism in this system.
