How can I make Dolphin open bookmarks in the current tab?

I have loaded the Dolphin browser on my HTC Android phone. Each time I open my bookmark it loads a new tab in the browser which means I have many running and I have to go in and close the tabs. Does anyone know how to make it use an existing tab of the browser? I don't want the browser to have so many tabs open. I realise this will mean if I have TWO apps the previous will show then open the bookmark. Alternatively, is it possible to have Dolphin close my tabs when the Home button is pushed?