beromir/Servas

use Illuminate\Database\Eloquent\Relations\MorphToMany;

class Group extends Model
{
    //
    public function links(): MorphToMany
    {
        return $this->morphedByMany(Link::class, 'groupable');
    }
    //
}

use Illuminate\Database\Eloquent\Relations\MorphToMany;

class Link extends Model
{
    //
    public function groups(): MorphToMany
    {
        return $this->morphToMany(Group::class, 'groupable');
    }
    //
}

class LinkController extends Controller
{
    //
    public function store(StoreLinkRequest $request): RedirectResponse
    {
        //

        $groupIds = $validated['groups'];

        $link->groups()->sync($groupIds);

        //

        return Redirect::route('links.show', $link->id);
    }
    //
}