In Norwegian the bigram "Aa" is usually sorted as "Å", but in some cases like "Aachen" this is wrong. The solution proposed by Unicode is to use either U+00AD SOFT HYPHEN and U+034F COMBINING GRAPHEME JOINER, but as the former gives a hyphen in some cases where it should not, like Aachen, the preference is often to use the later.
Thus create an "entity" cgj for COMBINING GRAPHEME JOINER.
For a description of the codepoint, see w:Combining Grapheme Joiner.
A more involved solution is given at T175802: Collation sequences, failed contraction matches in Norwegian