who knows. it could work for votes on particular bills or court appointments put before the house or senate, both factions -- traditional GOP and Trump party -- would both support, say, a conservation judge or tax cuts. the problem would be in elections, might be difficult at this point for a hardcore McConnell or Romney supporter to vote for a Trump party candidate (and vice versa).
also, our election system is all about campaign funding. In the average year, Dems and GOP get close to equal amounts of donations from various groups and individuals. a split GOP means that shifts it to Dems 50%, and trad GOP and Trump party dividing the other 50% (who know what percentage each). that means a big spending advantage to the Dems, which helps them win elections.