Matching two dataframes and pulling in a maximum value

I have two tables:

df_workingFile

      group   v   
1      a    110 
2      a    90 
3      b    57 
4      b    53  

df_groupIDs

  group   
1      a 
2      b  

I want to pull in the maximum value from df_workingFile for a group label into df_groupIDs

df_groupIDs

  groups   max
1      a   110
2      b    57

I have code that does this, but it's really slow with large datasets.

data.frame(df_groupIDs, maxValue = 
   sapply(df_groupIDs$group, function(newCol) 
   max(subset(df_workingFile, newCol == df_workingFile$group)$v)))

Any suggestions on how to make this more efficient?