When Document is released , set version as A or B or C

In Windchill OOTB Installation , default version schema is A.1,A.2,A.3...B.1,B.2,B.3

My requirement is , When the document is routed to lifecycle state "Released" document should be set to version as "A" or "B" or "C"

For Example , if a document of version A.16 is set to "Released" through a promotion request with default promotion approval/review process , then the version of released cad document should be "A" ( Similarly , If B.20 is set to released , released document version should be as "B").

Any insights on how this can be achieved ?