LDAP authentication filter based on source SSID

Hello! I need some help with RADIUS regarding Wireless authentication with RADIUS + LDAP. I need to check if the user has permission to connect to a specific SSID, so we check a LDAP attribute for that. By that, we need to know from which SSID the authentication is being requested so we use a specific LDAP Filter to search the base and grant or deny the permission. We tried to use two instances of RADIUS, one per SSID, but the Wireless Controller doesn't seem to support it (supports only one AAA per AP). That's why i'm asking for help in case you people have some alternatives or ideas to solve it. The setup is based on Cisco Wireless Controller 5508. Thanks in advance!