Realistically Ken, you need to get another program that permits you to parse your tree into separate branches. Ancestry's "Oh just make a copy, reload it under a different name and delete the names you don't want or need." You don't want to know how long it takes to remove 6,000 names from an Ancestry Tree.....trust me on that. LOL
On Ancestry I found it easier to create new Trees and replicate my work as this also permitted me to update some of those in my original file I may have added years ago and hadn't researched again. Always new data being added to Ancestry..
I used a product called Legacy once. Nice, but it costs some bucks. Family Tree Builder has a free version. but I haven't tried it so I can't say Yay or Nay on it. But it is free to try. A quick Google search also brought up Family Echo, never tried so don't know how good it is, but again...free.
Here is a Free Space Page I made up for GEDCOM users. I haven't updated it since last fall so some things may have changed, but the help pages it points you to would still be updated.
GEDCOM File Primer