Need solution to dynamic value list

[schmegol]

I have a need for a value list that updates when I update the master list of values in another related table but does not globally update all records where the list is used.

For example, I have "customer" table with radio buttons of various subscription rates that are populated by a value list in another table of "subscription rates". What I'm trying to do is when I update the  table of subscription rates it will NOT affect individual customer table records and update them. It only affects new customer records created and rates from when the "subscription rates" table is updated. So every previous record before the subscription rates table is updated to new rates will reflect the subscription rates the customer originally signed up for.

Right now my customer table is related to the subscription rates table with a global field that is the same for all records in both. My rates value list uses the related values from the subscription rates table but If I change a subscription rate it updates all the customer records.

[comment]

Modifying a value list does not change the values stored in a field using the value list. However, the display may be affected. Suppose you have a value list of "A¶B¶C" and a checkbox field with A and B selected, and you remove "A" form the value list, the field will not no longer display "A" - but it will still contain both "A" and "B" (use another instance of the field, formatted as edit box, to verify this).