Its not "lying" if it it part of the game. Deception is a part of most games. After all, in baseball the catcher doesn't yell out what pitch he wants the pitcher to throw. In football the offense will try to disguise its plays and the defense does the same. And there would be no poker if we played with the cards face up.
Deception as part of the rules of a game is not lying any more than using imagination to tell little children about Santa Claus or the Tooth fairy is lying.
In short, is your card game a sin? I doubt it.