To form into a league
To cause to join into a league, federal union, or similar association.
To ally (oneself, for example) with one side of an argument or cause:
To establish a rapport or relationship; relate:
Find another word for confederating. In this page you can discover 5 synonyms, antonyms, idiomatic expressions, and related words for confederating, like: leaguing, federating, allying, aligning and connecting.