You can influence the selection of servers at the same proximity level by adding a weighting value to the autofs map. For example:
/usr/man -ro oak,rose(1),willow(2):/usr/man
The numbers in parentheses indicate a weighting. Servers without a weighting have a value of zero and, therefore, are most likely to be selected. The higher the weighting value, the lower the chance that the server is selected.
All other server selection factors are more important than weighting. Weighting is only considered when selecting between servers with the same network proximity.