Page 1 of Scart Troubles

I`ve been looking for a device that will allow me to plug three scart leads into one socket without sucess. The first I tried was from argos, and could n`t handle RGB, only composite. Then I tried a JVC one from Dixons. This can handle RGB but not composite. Also plugging other scart leads into the block affects the picture or sound of the other signal. eg Dreamcast has no sound with DVD plugged in and off, and DVD`s colours are different with DC plugged in and off.
Is there a solution to this and can anyone suggest a suitable and reasonable priced product?

Thanks

BT21 - http://www.lektropacks.co.uk/acatalog/Lektropacks_Online_Scart_Controls_10.html