PnP Sharepoint - Add SP group to a library in another site

[zbrookesa]

Hi,

I have a site with multiple libraries and I want to add individual group permissions to each library. The complication here are the groups are not contained within the same site. I can manually do this via the SP library permissions tab. It finds the all groups and I can apply them without issue.

However, I cannot do this via the PnP commands i.e. Set-PnPListPermission ... The command fails as it cannot find the group as I suspect because the group is not part of the site where there library resides.

Has anyone come across this challenge before and now if its possible or not to do it.
As you can this okay manually I imagine there is a way of scripting it (he says hopefully).

thanks for reading