What happens when people of different provenance, profession, and individual interests are en route and share the same (sacred) places for short moments in time? How inclusive or exclusive are their activities and behaviour? What elements of their identities do they emphasise to show an affiliation or distinction? The paper reviews some Late Hellenistic and Roman places along the routes of the Arabian Desert (Wadi Ramm, el-Kanayis and Wadi Hammāmāt) where passers-by left inscriptions, imagery and structures in order to communicate with both fellow men coming to these places before or after them, and with the gods. Departing from the distinction of 'styles', 'bonds' and 'boundaries' (Eliasoph and Lichterman 2003) in groupformation, it explores whether and how merchants, indigenous people, soldiers, or workmen established groups through religious activity. By closely looking at location, preferred script, content, reference to former texts or images, and larger spatial embedding (intra-site and inter-site relations) the various strategies, adapted to situation and purpose of the practice, become manifest, and show a differentiation of groups in terms of spatial setting, while an on-going intermingling attests to openended communication.