You can do it by creating an alias that for example, if you use the format; $mid(text,[color:red]3,3)[/color] will split it into 2 $mid().
One that gets from, 1-2, and the other that gets from 6 on, alternatively use, $left().
alias nomid { return $left($1,$calc($2 - 1)) $+ $mid($1,$calc($2 + $3)) }
something like that, works just like $mid().
Eamonn.