Pues podrías probar algo tipo....
<input type="button" value="enviar 1" onclick="this.form.action='pagina1.asp';this.form. submit()" />
<input type="button" value="enviar 2" onclick="this.form.action='pagina2.asp';this.form. submit()" />
<input type="button" value="enviar 3" onclick="this.form.action='pagina3.asp';this.form. submit()" />
