Replacing row strings based on condition in column values

I have numerous datasets with the following format

> head(averagetable)
   Group.1     Moving   Feeding  Standing
1 cluster1 0.05632530 0.1722892 0.7503012
2 cluster2 0.09220779 0.2644481 0.6118506
3 cluster3 0.04863636 0.1268182 0.7993182

I'm quite new to R and but my assignment is simple:

1) I would like to replace the name cluster# in Group.1 by Standing in the row with the highest value in column Standing.

2) The name Moving/Feeding to the second highest value of column Standing

3) The name Feeding/Moving to the thirsd highest value of column Standing.

Hence the output:

> head(averagetable)
   Group.1       Moving     Feeding   Standing
1 Moving/Feeding 0.05632530 0.1722892 0.7503012
2 Feeding/Moving 0.09220779 0.2644481 0.6118506
3 Standing       0.04863636 0.1268182 0.7993182

Hope this was clear enough. I'm guessing ifelse is the function to use but I'm guessing a for-loop needs to be implemented an I'm unsure on how to do that.

Any input is appreciated!