package Foo;
use strict;
use warnings;

sub import {
    # print "Foo::import(): @_\n";  # debug

    shift @_;  # first arg not needed here
    my $dest = caller;

    for my $what (@_) {
        if ($what eq ':transforms') {
            no strict 'refs';

            for (qw(transform_one transform_two)) {
                
                *{"${dest}::$_"} = *{"Foo::Transforms::$_"};
            }
        }
        # elsif ...
    }
}

package Foo::Transforms;

sub transform_one{ return "transform_one(): @_" }
sub transform_two{ return "transform_two(): @_" }

# ...
1;