I read your message again and the exact process does not (yet) exist in Blue Kenue for what I was thinking.
A few years ago, in Green Kenue, I added the ability to map multiple grib files onto a Rect 2D Scalar... yielding a multi-frame Rect 2D Scalar where each frame was, in essence, a Map Object from the file onto the grid. In this case, File > New > Regular Grid... kicks things off with a grid that has no values... only the x,y co-ordinates of the grid itself. That work was mapping multiple grib files containing precip. At that time, Blue Kenue also gained that new functionality.
In your case, you I'd imagine that you would start with a mesh that has no values and then you'd want to do something very similar... map each grib file onto the mesh as a new frame. So that you'd end up with a multi-frame 2D mesh.
There a a few things that I'm checking on and that I'd like to add to Blue Kenue to make this possible for you and anyone else wishing to map wind, precipitation, etc. from grib files onto a 2D mesh.
That being said, this approach is not (yet) available and has been sitting on my TODO list for a while. If your need is urgent, then I'd suggest looking to a script approach... sorry.
Kindly,
Alan