Who could I combine two .fla into one main .fla file?

I actually want to know how I can connect two.flafile into one master or main.flafile

This is something like, on main.flafile thereare two buttoncalled 1.Previous,2.Next

When I click on NEXT it will the play.fla2 AND when I click on PREVIOUS that will play.fla1

Waiting for nice response

Regards,

Saiful