.htaccess - RewriteRule with 2 values -

url : http://siteexample.tld/index.php?a=profile&u=johndoe trying change url siteexample.tld/profile/johndoe if if a=groups siteexample.tld/groups/nameofgroup etc...

this htaccess far

rewriteengine on rewritecond %{request_filename} -f rewriterule ^(.*) $1 [l] rewriterule ^(([^/]*)+)(/([^/]{0,32})(/.+)?)?$  index.php?a=$1&q=$3    [l]