Modify project Dates, does not change the existing tasks dates

Hi,

Please advise best way to meet below requirement:

1) If we modify project transaction 'Start' and 'end' dates in projects form, the "existing Top Task'  start and end dates to be changed as per Project level dates.

2) If we modify existing Top Task transaction 'Start' and 'end' dates in Tasks form, the "its existing sub-tasks'  start and end dates to be changed as per its Top Task level dates.

3) Similarly, the budget lines start and end dates to be changed as per project level dates. (We use 'Date Range' or 'None' with or without 'Categorized by resources setup for budet entry methods).