custom dissector loop tree till packet data end

Hi,

I have a 3 parent trees

                     tree1
                          sub-tree of tree1 
                     tree 2 
                          sub-tree of tree2
                     tree 3
                          sub-tree of tree3

Now after processing my packet data of 1 frame , still i hae remaining data to be processed and which i have to call tree 1 again.

How do i do this? I have implemented tree1 a function tree 2 as a seperate function and tree3 as a seperate function.

how do i loop back whithout tvb offset. Is it possible for a function to return TVB and offset and length.

please suggest! Thanks in advance!