RobustToolbox/Robust.Server/Player/FilterSystem.cs

using Robust.Server.GameObjects;
using Robust.Shared.GameObjects;
using Robust.Shared.Player;

namespace Robust.Server.Player
{
    internal sealed class FilterSystem : SharedFilterSystem
    {
        public override Filter FromEntities(Filter filter, params EntityUid[] entities)
        {
            foreach (var uid in entities)
            {
                if (TryComp(uid, out ActorComponent? actor))
                    filter.AddPlayer(actor.PlayerSession);
            }

            return filter;
        }
    }
}