Diminuir codigo

Bom dia pessoal, tenho mais um problema para resolver... eu fiz um codigo que oculta e faz aparecer divs por id. O codigo esta rolando bem mas gostaria, se possivel, diminuir caracteres pois ficou muito repetitivo...

function ver1(){document.getElementById('c2').style.display='none';document.getElementById('c3').style.display='none';document.getElementById('c4').style.display='none'}

functionver2(){document.getElementById('c2').style.display='none';document.getElementById('c3').style.display='block';document.getElementById('c4').style.display='block';document.getElementById('c5').style.display='none';document.getElementById('cm1').style.display='block';document.getElementById('cm2').style.display='block';document.getElementById('cm3').style.display='none'}

function ver3(){document.getElementById('c2').style.display='block';document.getElementById('c3').style.display='none';document.getElementById('cm1').style.display='none';document.getElementById('cm2').style.display='none'}

function ver4(){document.getElementById('c2').style.display='block';document.getElementById('c3').style.display='none';document.getElementById('c4').style.display='none';document.getElementById('c5').style.display='block';document.getElementById('cm1').style.display='block';document.getElementById('cm2').style.display='none';document.getElementById('cm3').style.display='none'}

function ver5(){document.getElementById('c4').style.display='block';document.getElementById('c5').style.display='none';document.getElementById('cm1').style.display='none'}

function ver6(){document.getElementById('c2').style.display='block';document.getElementById('c3').style.display='none';document.getElementById('c4').style.display='block';document.getElementById('c5').style.display='none';document.getElementById('c6').style.display='none';document.getElementById('c7').style.display='block';document.getElementById('cm1').style.display='none';document.getElementById('cm2').style.display='none'}

function ver7(){document.getElementById('c6').style.display='block';document.getElementById('c7').style.display='none'}Eu ja tentei de diversas maneiras mas nao tive sucesso, exemplos:

function ver6(){document.getElementById('c2,c4').style.display='block';document.getElementById('c3,c5').style.display='none'}

function ver6(){document.getElementById('c2')('c4').style.display='block';document.getElementById('c3')('c5').style.display='none'}

function ver6(){document.getElementById('c2'),('c4').style.display='block';document.getElementById('c3'),('c5').style.display='none'}Alguma sugestao? Obrigada