We can't build that accurately for all cases yet, although there is a change planned which will let us.
Any time there is a 4-bet or higher by another player we do not know what position the 2-bet came from so we can't determine relative positions of the 2- and 3-bettors.
Assuming we can ignore those cases, the check for being in position is:
holdem_hand_player_statistics.position < holdem_hand_player_detail.val_p_raise_aggressor_pos
..so you could make new versions of the stat you're interesting in which check that (and the opposite for out of position). See the
Tutorial: Custom Reports and Statistics for how to build a new version of a stat.
If you want more help building the exact expressions you need, please let us know the exact situations you're interested in: for example do you want to include all calls of 3-bets, or only those where the player made the initial raise, or limped, etc.?