Refreshing Parameter Value

If there any way that I can set multi-value paramet to be selected as first value form the list down box.you can't to this by defautl values.
For example If I select A from the parameter 1, list values or 2,3,4 and I can select first value which is 2. Then I have another parameter B and related values are 1,2,3,4
If I select A first and I will get the second parameter values 2,3,4 and defautl is 2. If I select parameter1 again B, then i will get the 2nd parameter valeus 1,2,3,4 but it default will be 2 where it should be 1
However, If I select B first ebfore selecting A, I get the default value as 1 which is the correct one. I fell it is a bug. Not sure.