Ontario has Stamkos, Tavares, Giroux, and Perry at forward; Subban, Burns, and Doughty on defence. Goalies are weaker (Mason, Elliott, Murray).
You'd have to combine all the Maritime provinces and even then it would just be Crosby, Mackinnon, Marchand, Killorn, and Purcell. Their defence would be McQuaid and MacDonald, and Jake Allen would be their starter.
Quebec would be competitive with Bergeron, Huberdeau, Brassard, Duclair, and Drouin. Defence is quite strong with Letang, Vlasic, Demers, and Scandella. Goalies are Luongo, Fleury, and Crawford.
Looking at the prairie provinces, Manitoba has Toews, Sharp, Steen, Keith, and Reimer. Saskatchewan has Getzlaf and Holtby. Alberta has Hall, Little, Bouwmeester, and Green, but their goalies are Scrivens and Johnson. You could combine them into a fairly good team.
BC could probably field a team of its own with Benn, RNH, Johansen, Ladd, Weber, Seabrook, Barrie, Price, and Jones.
But since this is 5 teams, have a 6th International team made up of the other countries.