Similar word to tieup:

affiliation, alliance, band, bunch, circle, clan, clique, club, coalition, combination, combo, company, confederacy, confederation, congress, cooperative, corporation, crew, crowd, family, federation, fellowship, fraternity, gang, guild, hookup, league, mob, order, organization, outfit, partnership, pool, rat pack, ring, society, sodality, sorority, syndicate, tie-in, tie-up, tribe, troops, troupe, union, zoo