sed replace using wildcard
===

How can I carry out the replace below with sed?

input

    group0 group1 n_name_0 n_name_10 n_name_20 n_name_5 n_name_40 team0 team1

required output  

    group0 group1 n_name n_name n_name n_name n_name n_name team0 team1

I tried using sed -i 's/n_name*/n_name/g' but it deletes everything after n_name
