Frank Lupo reportedly will become an exec producer next fall on CBS’ “Walker, Texas Ranger,” in the process cutting in Columbia Pictures TV — where Lupo has an overall deal — as a partner on the Chuck Norris series.The show is slated to be produced by Cannon Pictures in association with CBS Entertainment Prods., which opted to come to the rescue after Cannon ran out of money producing the show for its spring run, supplying only four of the 13 hours ordered. The deal would apparently be patterned after Columbia’s pact with NBC Prods. on its TV movies starring Bill Cosby, in which the studio made show runners available (in that case, William Link and David Black) for handling certain distrib rights on the series. Columbia, in fact, now has some sort of alliance with each of the three networks, having also entered into an arrangement with ABC Prods. where the parties will jointly produce the hour series “Do the Strand” and share in its back end. Such arrangements make sense for the webs, since even under the relaxed version of the financial interest and syndication rules networks are required to engage third parties to handle domestic distribution of series they produce. Columbia declined comment, and CBS officials — in New York for the affils meeting — couldn’t be reached.