How to can we manage Position HeadCount based on positions sub level.

Hi,

We need to manage Position Head Counts based on positions parent and sub levels. For example we have three positions of one parent position, let's say Clerk is main Position and Junior, Mid level and Senior clerks are three sub positions. And we have only 1 position for Clerk.

How can we set headcount for all three positions so that system should validate and allow only employee to hire or promote on Clerk position.

Thanks,

Faisal.