Just in case others are interested I ended out with this script:

===============================================
#/bin/bash

for arg in $@; do
        if [[ "${arg}" =~ "^\-" ]]; then
                EMERGE_ARGS="${EMERGE_ARGS} ${arg}"
        else
                BINARIES="${BINARIES} ${arg}"
        fi
done

PKG_LIST=`which ${BINARIES} | xargs -r ldd | awk '$2~/^=>$/{print $3}' | \
	sort -u | xargs -r equery belongs | sort -u | while read pkg; do grep -q \
	splitdebug /var/db/pkg/"$pkg"/FEATURES || echo ="$pkg"; done | xargs`

if [[ -n "${PKG_LIST}" ]]; then
        emerge --verbose --oneshot ${EMERGE_ARGS} ${PKG_LIST}
fi
===============================================

This allows me to run it with -a or --ask to avoid having to wait for equery 
and emerge twice.

Thanks Richard. :)

-- 
Bo Andresen