[Placement Driver] Merging regions based on a custom decision

I want to merge regions based on a custom configuration. I had in mind to do it using a plugin, but it seems the merge_checker happens automatically called by Controller.CheckRegion https://github.com/tikv/pd/blob/f61664b74d3910692d11e01e32dc12d2c06a60b4/pkg/schedule/checker/checker_controller.go#L129-L137

I see that TiDB added to PD a function to infer the table name + a parameter called enable-cross-table-merge to know if it should merge regions together or not. However I would like to avoid to do the same. Do you see an easy way that doesn’t require to change the current code, hence the reason I was mentioning a plugin. I wonder why it does it automatically if we then have scheduler that are there to manage this part AFAIU.