internal bgp question

Have a situation .. It is necessary to link two Rout server (internal bgp) by cat6509 approximate scheme: rs1 (vlan1, as1111)-c6509 (as1111) - rs2 (vlan2, as1111) In this configuration, protocol bgp c6509 { local as 1111; neighbor 178.xxx.xx.x as 1111; error: Only external neighbor can be RS client how can I get out of this situation and to link both route servers internal bgp? without the use of gray AS