Answer:
Assume the player 1 be denoted by j1, player 2 by j2, player 3 by j3, player 4 by j4, player 4 by j5.
If player j demands the salary cj, then the IP can be formulated as follows:
Objective:
Minimize:
cj1+cj2+cj3+cj4+cj5
Subject to:
1. cj1 = cj2 (Player 1 and 2 shoukd be signed together)
2. j1+j2+j3+j4+j5 =3 (3 players should be signed from 5 players)
3. j1+j2+j4 >=1 (Atleast 1 player must be chosen from player 1,2 and 4)
4.sj1+sj2+sj3+sj4+sj5 >= S units (Strengths of the player must be S units)
5. aj1+aj2+aj3+aj4+aj5 <= A quota (Penalties must be less than A quota)
6. j1<j3 or j3<Ji (Player 1 and 3 will not come together)
7. j1,j2,j3,j4,j5 >=0 (Non-negative constratint)