Hey Ronaldo,
Merging procedure is here - http://scn.sap.com/community/netweaver-administrator/blog/2012/08/20/combine-multiple-transport-requests-into-single-transport-request.
As far as object content is concerned, its a nice question and i also do not know the behavior so looking for others replies or maybe once i am in front of SAP system will check out myself.
BR.