As we usually work on multiple repositories , we list the pending merge-requests for a single repository(current repo) in github/gitlab UI.
Is there a way to configure a system , where all pending merge requests for a given number of repositories can be viewed altogether ?
You can use API. For example, if you are using GitLab you can query the API to get a list of open merge requests
GET /merge_requests?state=opened
You can find more info here
You can build a GitLab pipeline that will query GitLab API for open merge request id or URL for specified project IDs