How to add more lines on free pabx

I am quite a newbie in the asterisk box, i have 2 FXo cards installed on the server each with 8 ports, totaling to 16 incoming lines, i have been only using 3 lines ( GSM / GPRS fixed wireless terminals ) i have purchased 3 new more and want to expand the number of lines for outgoing/ incoming calls.

Tried to install the Units in there respective ports eg 125,126,127,128,129,130, and configured the Admin Panel by adding the Dad-hi trunks and giving them the respective Dahdi identifier and Trunk Name.

On the Outbound routes i have 2 Routes grouped , VODACOM and ORANGE where each group i have split the 6 lines to 3 on each route on the trunk sequence. Each route has its own dial pattern when calling to there respective service provider.

My problem comes that i can not make more than 3 concurrent calls from either route or on both route, I would like to know if there is any other configurations/rules that i need to do so i can have all the six lines to make concurrent calls at any given time.

guys…dose anyone know how to do this … ? ? ?