COUNT of AGGR of second minimum when one field <> another field

[#1]

The master table contains the following columns:  "Trans_Id", "Field1", "Field2", "Field3" and CP

I have created a INPUTFIELD column "USER_CP_SELECT". The table contains "Field1" and "USER_CP_SELECT" where user can enter the "CP" he wants to exclude from the calculations. (USER_CP_SELECT could be NULL or may different for each "Field1").

Now I want to find out for each "Field1" count of distinct "Field2" which has 2 or more "Trans_Id"  where "Field3" <=100 and "CP" <> USER_CP_SELECT

Here I want to create a for trend graphs for "Field1".

Chart Dimension is "Field1"

COUNT(DISTINCT AGGR(MIN({<Field3={'<=100'},CP={"=CP<> USER_CP_SELECT"}>}Trans_Id, 2), Field2, Field2, Field1))

Above expression works if I have selected only one value in "Field1", but does not work when multiple values are selected in "Field1".

Then I tried the below expression which works fine for multiple "Field1" selections but only finds FIRST minimum and I don't know how to find SECOND minimum.

COUNT(DISTINCT AGGR(MIN(if(Field3 <=100 AND CP <> USER_CP_SELECT,Trans_Id)), Field2, Field2, Field1))

Can someone help solve this problem?

Let me know if you need more data.

Thanks in Advance!

[#2]

To find the second minimum you can use rank function.For example if want to find the second minimum of sales based on country you can use it like

=aggr(min(sales,2),country)

[#3]

Yes, I know how to use simple aggr to find second minimum, but my question is different.