FM24 pre game editor

Hello guys, i need a little bit of help..the thing is that i want to create database with legends (all time) and i saw that there is already database created from another guy but have somethings that i want to change (for example there are few nations created like sssr, yugoslavia, czechoslovakia...which i dont like)..can i delete those nations or is there any other solution? Also is there possibility to make a fusion between 2 databases, or i need to do all this manually? To make it clear i want to insert in database players from other database (David had very good database on fm20, return of the legends, but unfortunately he doesnt have any more time to do it) and he missed some legends which exists in all time database. Maybe this is stupid post but i had to ask..Thanks in advance for any helpful replies.