Variations of the same data source API are treated as different data sources (credentials & privacy)

I found a workaround/solution for my problem. Looking at the official documentation I found out that "the M engine identifies a data source based on the required parameters of the custom connector". I changed my custom connector so that only the common part of the API URL is regarded as a required parameter and the other parameters (including the end part of the URL) are regarded as optional. This way Power BI stores credentials for the data source based on the common part of the API URL and uses those credentials for all calls to the API with the same common part of the URL.