Citroen c5 estate 2005 JBL system fitting

[lasiakutevs]

Hi all I have a question that need answering im trying to do a rt3 conversion and got the hole dashboard with intact wiring and looking at the wiring there is a grey connector, I think it for speakers to connect to jbl amp but i cant find the connector in my car so the question, is there a connector where all speakers wires come to in a non jbl audio system or not
I can make fotos of the connector if it wound help

Sorry for bad English