I have a problem wherein I need to establish a connection $o$ of type $t$ between two locations $f1$ and $f2$ provided there is an interface $n$ of type $h$ activated at location $f1$ and location $f2$ and the capacity of the connection $o$ of type $t$, cap$^{t,o}_{(f1,f2)}$ doesnt exceed the interface capacities, cap$^{h,n}_{f_1}$ and cap$^{h,n}_{f_2}$ at both the locations. I am finding it really hard to couple these variables. A solution that I tried to work out is as follows:
$\theta^{t,o}_{(f_{1},f_{2})} \leq \theta^{h,n}_{f_{1}} \hspace{2cm} \forall o\in O, t\in T, n\in N, h\in H, (f_{1},f_{2})\in L_s\\[2ex]$ $\theta^{t,o}_{(f_{1},f_{2})} \leq \theta^{h,n}_{f_{2}} \hspace{2cm} \forall o\in O, t\in T, n\in N, h\in H, (f_{s_1},f_{s_2})\in L_s \\[2ex]$ $\theta^{t,o}_{(f_{1},f_{2})} \geq \theta^{h,n}_{f_{1}} + \theta^{h,n}_{f_{2}} \hspace{1cm} \forall o\in O, t\in T, n\in N, h\in H, (f_{1},f_{2})\in L_s \\[2ex]$ $\text{cap}^{t,o}_{(w,f)}\theta^{t,o}_{(w,f)} \leq \sum_{h\in H}\sum_{n\in N}\text{cap}^{h,n}_{f}\theta^{h,n}_{f} \hspace{2cm} \forall t\in T, o\in O, f\in F$
But I'm pretty sure that the above solution is wrong. Can you please give me some suggestions to fix the problem?