We have examined the spatial distribution of 856 AGN detected by the ROSAT All-Sky Survey ( RASS ) using a direct search for structures with the minimal spanning tree .
The AGNs were compiled from an area of \sim 7000 deg ^ { 2 } , in which optical identifications of RASS sources were made with the help of the digitized objective prism plates of the Hamburg Quasar Survey ( HQS ) .
Redshifts were taken from the literature or from own follow-up observations .
The sample probes the spatial distribution at low redshifts , since the redshift distribution peaks at z \sim 0.1 .
The application of the minimal spanning tree led to a 1.8 \sigma discovery of an AGN group with 7 members in a volume V \sim 140 \times 75 \times 75 h ^ { -3 } Mpc ^ { 3 } in the Pisces constellation .
With a mean redshift z=0.27 this group is only the third discovered group at redshifts z < 0.5 .
The RASS offers excellent possibilities to study large scale structure with AGNs at low redshifts , once these redshifts are determined .