They wouldn't even know them if they saw them. My parents are the only grandparents they know.
Yes it is possible. A will can be used to limit that possibility, however, there may be problems.
Another possibility is for your parents to "adopt" your children under the Kansas parentage act and the case of Frazier v. Goudschaal, 296 Kan. 730, 295 P.3d 542 (2013). The parentage act "adoption" does not sever your parental rights but establishes new parental rights and responsibilities and prioritizes the rights and responsibilities between the adults (as is done in a divorce). In your case, the parentage act "adoption" results in your children having 4 parents with your parents being "stand by" parents in case of your death or disability. Your parents would need to write wills (or otherwise revise their estate plans) to make the results fair for all of their children.
Discuss this possibility with your lawyer.
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