Simple (?) Mail-merge software

Goal: basic mail merge, *BUT* each letter needs to have two lists within it. List A is a list of names - with the name of the recipient of THAT letter MISSING. List B is a list of companies, with the name of the company THAT letter's being sent to MISSING. --make sense? I must be able to enter all the names into a List A database, and all the companies into a List B database - and have the mail merge 'know' to eliminate the name Mr. Smithers from List A on the letter addressed TO Mr. Smithers AND eliminate the company Mr. Smithers works for from List B ON Mr. Smithers' letter. example: Letter 1 would say... Dear Mr. Apple of AAA company, Blah blah -- this letter is also being sent to these people Mr. Ballyhoo, Mr. Carrot, Mr. Dinkins [etc.](((Mr. Apple missing from this list))) This letter is also being sent to BBB company, CCC company, DDD company [etc.]... (((AAA company missing from this list))) - - - - THEN, letter 2 would say... Dear Mr. Ballyhoo of BBB company, Blah blah -- this letter is also being sent to these people Mr. Apple, Mr. Carrot, Mr. Dinkins [etc.] [Mr. Ballyhoo missing from this list] This letter is also being sent to AAA company, CCC company, DDD company [etc.]... [BBB company missing from this list] and so on. Resulting software must be able to be used with/through already-existing standard word processing software, if possible. Open Office, Word. etc. Ideally it would be an 'add-on' if possible.(?) I would own the software + all rights to it (exclusively). Thanks. -- TW