The way I handle it is to put them on rest and stick them in the back for everything unless they are actively in an operating seat. Otherwise they will not get the required 3 hours to extend the duty (assuming 60 from boarding to TOC, 90 TOD to TOC, then 30 TOD to DXB).
Unless the pairing has been specifically listed as a "burnout" per vp-ops, everyone must get the 3 hours somehow.