Is there a way to use one config to deploy multiple applications?

I have one big application built on an SOA architecture. Those. there is a main client and a bunch of deployed services and services. All of them have their configs. Almost all of them use the same database in their work. Accordingly, everyone has a ConnectionString to the database in the config. That is exactly what is not like it. I just want to specify ConnectionString in one file and all other configs should pick up, and not specify the same connection string in dozens of configs for all services. Is there any possibility to put this ConnectionString in some global config / file / something else? Machine.config can not be used (or rather, I really do not want to touch such system configs). Are there any solutions to this problem? Someone probably has knowledge in continuous delivery, tell me.