Keeping Projects and making old customers inactive

Hi everyone, we are a construction company. As such, most of our customers are one-and-dones, tho we occasionally do have repeat business. In reconciling bank transactions, costing expenses to projects is becoming increasingly burdensome due to the overflowing number of customers that must be sorted through to find the correct Project. QBO apparently is not capable of setting old customers to Inactive if they have a Completed project attached. Has anyone found a viable work-around for this that does not involve de-coupling the Project from the Customer? We want to keep Customer data around, because we do occasionally have people come back to us for new Projects later on. And of course we want to keep our Project history as reference for future Projects and profitability. Any tips appreciated.