Oracle multiple databases on same server
You can use the Multitenant option, create a container database, create 2 pluggable databases called db1 and db2, then import the first dump file to db1, the other dump file to db2.

You can switch between pluggable databases with as:

alter session set container=db1;
alter session set container=db2


But this requires at least version 12c, and it is an extra cost option.

For lower versions, or without the Multitenant option:

Simply create 2 traditional databases on the server: db1 and db2. Import one dump to db1, the other to db2. You can specify in your connection string the service (or SID) for the database you want to connect to. For example:

sqlplus user/password@hostname/db1
sqlplus user/password@hostname/db2