Multi tenancy Implementation

I am looking around for a multi tenancy ORM tool to use in my Java
application

I have the following situartion

a primary customer table

Customer ID  Customer Name  Jndi Datasource

1                   Mrx                    jndi 1
2                   Mry                    jndi 2

at run time based on which customer is logged , i want to call different
jndi's. Each jndi posts to different dbs but shares the exact same schema

For purpose of isolation i cannot store all information in one table/db and
discriminate each row by Customer ID

Any help would be great , as based on this i am hoping to use cayenne

Thanks
Vinod