  We have successfully developed a technique to integrate an automatic
event-generator generation system GRACE and a general-purpose event generator
framework PYTHIA. The codes generated by GRACE are embedded in PYTHIA in the
created event generator program. The embedded codes give information on
parton-level hard interactions directly to PYTHIA. The choice of PDF is
controlled by the ordinary parameter setting in PYTHIA. This technique enables
us to create easy-to-handle event generators for any processes in hadron
collisions. Especially, in virtue of large capability of GRACE, we can easily
deal with those processes containing many (four or more) partons in the final
state, such as multiple heavy particle productions. This project is being
carried out as a collaboration between the Japanese Atlas group and the
Minami-Tateya group, aiming at developing event generators for Tevatron and LHC
experiments.
