Validate the ranges do not intersect

I'm trying to implement an MDS entity to be used to create ranges (From/To) and connect these to a group.
Now I need to be able to validate that changes made to range do not create an intersection with another range.
Example if I have the following in MDS:
Row From   To    Group
   1      1       3        A
   2      4       5        B

...then I should not be able to enter 2 as From-value in row 2 since this intersects with range of row 1.

Any ideas on how this validation can be made?

Best Regards,

 Per