Currency conversion only on one row

I have a custom column called CZKTOEUR:

[total] / 24

We have one store from all of our stores, which uses another currency. I would like to make the conversion in the table by an average ammount (24 in this case). I tried to make a custom expression in a summary like this, but it doesnt work:

case([storename] = "store1" , SumIf([CZKTOEUR], [transcationdate] = relativeDateTime(-1, "day") AND [CZKTOEUR] > 0),  SumIf([total], [transactiondate] = relativeDateTime(-1, "day") AND [total] > 0))

I want my total to appear in one column with the other stores, not a separate one. Any idea how to make it work? I would rather not convert the question to SQL, as I'd like to have access to all the filters etc. Is it even possible? Thanks