Shamir secret sharing with two types of parties Consider the Shamir Secret Sharing scheme based on polynomial interpolation.

In this scheme, every part has the same right: one piece of information of same value as the other ones.

The idea is to adapt this scheme in following way:

Suppose that we want to share a secret among politicians and generals.
The secret can only be retrieved if 3 elements are united and if in that group at least one is a politician and at least one is a general.

How can we do that? It is not clear to me what to do. Thanks in advance.
Let's say your secret is $S$. Split $S$ into 3 parts (say $S_1,S_2,S_3$) such that $S=S_1\oplus S_2\oplus S_3$.

Give each politician a copy of $S_1$, each general a copy of $S_2$, then split $S_3$ using 3-out-of-n Shamir Secret sharing.