As said above, and also it pretty much depends on how the hero selection is made. If it's just simple training from the Altar, then use as said above to all other heroes that are available. If it's something else, like Hero Tavern, it's a bit more complicated.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.