[Topogun] is it possible to retopo differents objs ?

HI everyone I would like to retopog a character in topogun ,  I sculpted in zbrush and use polygroups and differents subtools.

I would like to export it to topogun to begin with retopo , however I do not like to merge all the subtools in zbrush and export it...cause I think if I merge all together...(mouth, teeth, eye, tongue) with the main mesh (body and hair) will be a mess to retopo... I need a tool or some trick in exporting process to hide things in topogun.... interior or the mouth and teet is a pain to retopo if I joined together from zbrush.

In this picture I can explain it better. 

here are my subtools in zbrush (tongue , teeth , eyes ) in zbrush are subtools (not merged )  I keep all the polygroups and subtools at to the end,  in some cases I used to join all together to decimated,  but I noticed when I try to bake normal maps and all that will be a mess... I would like to retopo my complete character , full body and this pieces in topogun ... is it possible ?  does existe a tool in topogun to allows me to make my topology easy ? or should I retopo the body in topogun and go for my 3D package and retopo those parts (mouht, teeth) there? .