As voters in six states head to the polls for primary elections today, they should be feeling highly valued: Outside groups have shelled out nearly $11 million trying to influence how they will cast their ballot. Almost all of the money has been spent in Republican primary elections, reflecting the party’s continuing, costly rift.

An analysis of independent expenditures — money spent by committees other than the candidate — gathered by Sunlight’s Real-Time Influence Explorer shows that all of the spending had concentrated on four states — Georgia, Idaho, Kentucky and Pennsylvania.

The top money magnet is the hotly-contested Senate race in Kentucky, where groups for and against the reelection of Senate Minority Leader Mitch McConnell have spent more than $5 million. Next on the list is a surprise: the primary election in Idaho’s 2nd Congressional district has attracted a $2.9 million spending spree as Tea Party-backed Bryan Smith tries to knock off GOP Rep. Mike Simpson. That’s more money that outside groups have spent in the super-crowded GOP primary for Georgia’s open Senate seat.

Among outside groups, the biggest spender is Kentuckians for Strong Leadership, a super PAC that has spent $1.8 million to help McConnell win reelection to a sixth term in the Senate. The U.S. Chamber of Commerce spent $1.7 million backing both McConnell and Simpson. The other members of the million-dollar club are all groups that have backed GOP maverick fiscal conservatives against the party establishment: Ending Spending Action Fund, Citizens for a Working America PAC and the Senate Conservatives Fund.

While most of the top spenders are national groups active in elections across the country, there are some surprises. Professional organizations have combined to spend just under $950,000 on independent expenditures in Tuesday’s races. Political committees representing national organizations of realtors (almost $300,000), dentists ($247,000), credit unions ($156,000), hospitals ($137,00) and radiologists ($108,000) have all spent six figures boosting incumbent Republicans in Kentucky and Idaho.

In Georgia, the open seat left by retiring Sen. Saxby Chambliss, R, has attracted a gaggle of Republican candidates, but the vast majority of outside cash has supported David Perdue, a former executive at Dollar General and Reebok who seems likely to pull ahead on Tuesday.

None of the Republican party’s national arms have made significant independent expenditures in this batch of primaries, apparently waiting until general elections to throw their muscle behind a candidate.