Export/Import/SQL Loader :: Assigned To ROLE X Be Transferred To Role Y Via Datapump Import

i have user with the name 'Rob' and this user has been assigned a role 'MY_SRC_ROLE' . I developed a table under rob schema and granted access to this table via role GRANT DELETE, INSERT, SELECT, UPDATE ON rob.emp TO MY_ SRC_ ROLE; I have 100 more users & they have been granted this role 'MY_SRC_ROLE'. These 100 users can now access emp table via Role 'MY_SRC_ROLE' without any issues. Now i took a datapump export & performed datapump import on target server which is also HP Unix with 11.20.3 .

On target server i have user 'JACK' and a role called 'MY_WORK_ROLE'. 5000 users have been granted 'MY_ WORK_ ROLE' on this server. I have used remap tablespace clause & remap schema clause in datapump import script. Once i performed an import , due to schema remap , i can see JACK now owns table 'emp', however grants are still not there, I tried searching on Google & oracle documentation, if somehow we can remap ROLE GRANTS also while doing datapump imp, but i couldn't find supporting syntax. can i assume datapump import is not capable to handle this particular scenario ? I was able to do it by manipulating sqlfile and replacing role name in that but i am looking for a sol. within datapump itself. how can grants assigned to ROLE 'X' be transferred to 'Role Y' via datapump import.