Exclude files from merge

I want to exclude some file from merge, according to the search in google came to know that it can be achived through gitlab merge drivers the option is not working when applying merge from web interface or either cli. and we have tested the option in both gitlab ce and gitlab ee core. So please can somebody help me out to enable this option for merge divers globaly on server side.

Also some body said that it will only initiated on merge conflict but my required is that it should have to work if their is not conflict

My requirement is our brahces have different database configuration file and the parameters are different at both so need to exclude those file at every merge. So i cannot make conflicts again and again to make the merge trigger to work.