Maybe wrap the constant template with a list that makes sure that the current item is not already covered as a Greek letter?
<$list filter="[is[current]!tag[greek]limit[1]]"> <$list filter="[is[current]tag[constant]]"> ... -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/tiddlywiki. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/14ef92e1-1479-4a8d-99de-a19b1ccd0e3b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.

