Discriminate each local Administrator in user mode

If I've all clients deployed as "user mode", could I discriminate for each local Administrator account (ie Administrator on pc1 belongs to one group, Administrator on pc2 belongs to another group) or is this not possible?

I thought that the workgroup or domain was identified by the hostname but I've seen that SEP call it "LocalComputer" so I can't choose.

Is this correct? Any idea to override this limit without switching to computer mode?

Thanks in advance