We need following fact.
Lemma: Given a point D on side BC of the triangle ABC. Let ω1(O1,r1),ω2(O2,r2) be incircles of triangles ACD, ADB and ρ1(O3,r3),ρ2(O4,r4) be circles inscribed in these triangles externally, which tangent at an internal point of BC. Then lines O1O2, O3O4, BC pass through a point.

Proof of lemma: Denote BC∩O3O4=X and let's prove that X∈O1O2. From the well known property that a line passing centers of circles inscribed in an angle is bisector of the angle, it follows A=(O1O3)∩(O2O4), D=(O1O4)∩(O2O3). Since the line O3O2 intersects sides of the triangle AO1O4,
by Menelaus theorem we get 1=O3AO3O1⋅DO1DO4⋅O2O4O2A=O3AO3A−O1A⋅DO1DO4⋅O4A−O2AO2A
=(1−O3AO1A)⋅DO1DO4⋅(O2AO4A−11)=(1−r3r1)(r1r4)(r2r4−11)
=r3(r3−r1)⋅r1r4⋅r4−r2r2=r3r1(r4−r2)(r3−r1)r4r2(∗)
To prove X∈(O1O2) is equivalent to proving by Menelaus theorem:
XO4XO3⋅O1O3O1A⋅O2AO2O4=1.
Furthermore,
XO4XO3=r4r3,O1O3O1A=O3A−AO1O1A=O1AO3A−11=r1r3−11=r3−r1r1,
O2AO2O4=O2AAO4−AO2=AO2AO4−1=r2r4−1=r2r4−r2
and by (∗),
XO4XO3⋅O1O3O1A⋅O2AO2O4=r4r3⋅r3−r1r1⋅r2r4−r2=1.
This proves that X∈O1O2 and points O1O2, O3O4, BC pass through a point.
Now solve the problem. Let l be common tangent to circles ω1,ω2,ω3,ω4 which is different from BC. Denote l∩BC=X. Centers of circles ω1,ω2,ω3,ω4 lie on the bisector of angle formed by l, BC and the point X lies on this bisector too.
Using the lemma for triangles ABE, ADF, AEC we conclude that centers of circles ρ1,ρ2,ρ3,ρ4 and the point X lie on a line. Reflecting BC about this line we get a line which is common tangent to circles ρ1,ρ2,ρ3,ρ4. Thus we have the desired result.