I need a form to set up records

The table is something like

AutoID, Sequence , Low, High

Data would be

1, 1, 1 499
2,2,500,999
3,3,1000,9999
4,4,10000,999999

etc

Ho do I go about ensuring my sequences are correct

ie I wouldn't be able to add a record - 5,5,100,200

or if a user was to delete a record the user would be informed the sequences were out?

Thanks for any assistance.

Paul:
Took a crack at it. This might offer ideas.
Mark

Thanks - That looks to be exactly what I need.