Delete rows from dataframe that already aggregated

Question

I have a dataframe DF like this :

Cluster OS    Browser Pages  Convert 
0-5     11     16     100      10
0-5     11     17     100      5
0-5     11     16     101      10
6-9     11     17     100      10

that I then, group rows by : (Cluster, OS and Browser) to get a resulting dataframe DF2 :

Cluster  os_id      browser_id    page    convert
0-5       11           16       100, 101     20
0-5       11           17            100      5
6-9       11           17            100     10

Then, I would like to merge (concatenate) these 2 dataframe , but i should delete these rows because tehy are alredy grouped in DF2 :

Cluster OS    Browser Pages  Convert 
    0-5     11     16     100      10
    0-5     11     16     101      10

Any idea please to do it in python? Thanks