Problem summarizing formula using running total (or equivalent formula).

Hi, I am new to this, hope anyone can help. I am using Crystal Report 2013. I have made a formula returning a 0 when a running total is positive and returning a 1 when the running total is negative. I now would like to summarize the 1's on group level, but cannot use the summarize tool. When I make a summarize formula myself, I get an error, that it cannot summarize the field. I have tried to avoid the running total, by making this in a formula as explained on a number of forums, but this did not get me anywhere. The strange thing is, that I can amend the 1's and 0's as number by giving them a digit etc, so the report thinks it is a number, however when I want to make a sum, it is handled as text (boolean). Hope it is clear 😊 what I am looking for.