Grafana - datasource as variable

Question

I have one InfluxDB database, and a lot of buckets and a lot of datasources (where one datasource = access to one bucket). As You see, schema is simple: each datasource (named influxdb-clientXXX-r) have access only to one bucket (named clientXXX) where XXX is 100, 200, 300, etc. And now, how I can use Datasource as variable? it is important for me, because I want to isolate access for buckets, so I do not provide to Grafana datasource with access to all buckets. Probably I need dashboard variables, where each variable will be converted to datasource and bucket. So if user choose variable "100", Grafana should use influxdb-client100-r as datasource, and in query, Grafana should use in query from(bucket: "client100").

I cannot do one datasource with access to all bucket, because in that case Grafana user when will be edit dashboard, can change bucket to another, but I want protect platform before this, so I create separated Datasources (where one datasource = access to one bucket).