@karstenkoehler thanks a lot for such a detailed solution. The first two would have definitely worked if the Associated Deals of contact were actually equal to the no. of transactions. My bad for not giving enough details, but we have a different prospecting pipeline and even in the transactional pipeline the deal has a chance of moving to the lost stage. An additional filter for only closed-won deals would help do this job. I actually do these operations almost on a quarterly basis in sheets, but having it in HubSpot would help save a lot of time.
Although this gave me an approach that I’m gonna try. I’m thinking of going for a deal-based workflow that triggers when the deal is moved to the closed-won stage. The next step would be to check if the contact’s lifecycle is customer and tag deals as first or repeat. Will have to be mindful of choosing the close date as after 'm/d/yr’ threshold date*.* For deals before the threshold date, good old ‘export-sheets-import’ would do.
The third workflow looks very promising and I think it should do the job. Gonna try it all out very soon and back here.
Thanks again for the help!