Playing the "parental alienation syndrome" card it possible, but it is definitely an uphill battle all the way. In the U.S. a judge can force shared and/or joint custody of minor children. But judges can do little or nothing to prevent a parent from alienating their children against another parent. Nothing.
If the alienating parent is successful, the children will absolutely shun the other parent as soon as they become of age.
The psychological means of manipulation employed are powerful, generally applied unconsciously (although cult members have learned them well) and not subject to any legal means of prevention, redress or judgement.
It's a challenging read, but for those that undertake it, you will clearly understand the power of the psychological forces involved.
A relatively quick primer can be found here: Parental alienation syndrome