According to what erol's said,Thats not allowed.
Lock one of them
http://www.maxcheaters.com/forum/index.php?topic=196333.0
http://www.maxcheaters.com/forum/index.php?topic=196332.0
undig+link dont work+someone warn the undigger
http://www.maxcheaters.com/forum/index.php?topic=119427.0