Alcatel Unleashed

We have the following need:
There are two teams (A + B) each with a team hunt group.
We want to do the following:

When team A is on a holiday we need all call to team A hunt group or individual (associated set is the hunt group) to go to the hunt group of team two.
We want the teammembers to be able to initiate the take over themselves. So team A goes on holiday and one user can make the "forward" to the other hunt group active.

Any idea on how we can accomplish this?

From my point of view the best way:
1 - when user from HG A on holiday (BEFORE holiday) - users need to dial prefix for exit from HG.
2 - HG B managed like overflow (in HG A, or in HG A Entity CDT).

Variant 2:
1 - manage virtual set with forward to HG A
2 - for HG A calling - dial virtual set number
3 - when you need change destination (HG B instead of A) - reprogram forward (from any set via substitution)