[Groff] groff and specials question

[Gaius Mulley]

I wonder whether someone has a simple answer to this question.

I'd like to force troff to change it's font before a special.
Is there an easy way to do this? Here is a tiny example:

----------- file spec.n ------------------------
.LP
.SH
My Heading
.LP
\&\X^foobar^
and this text
----------- end of file spec.n ------------------------

troff -ms spec.n

yields the following ditroff output:

x T ps
x res 72000 1 1
x init
p1
x font 6 TB
f6
s10000
V84000
H72000
tMy
wh2500
tHeading
n12000 0
V99600
H72000
x X foobar
wx font 5 TR
f5
h2500
tand
wh2500
tthis
wh2500
tte
H115460
txt
n12000 0
V768000
H504000
n12000 0
x trailer
V792000
x stop


note that the font changes back to font 5 after x X foobar and not before.
I'd like to invisibly force troff to change back to font 5 before x X foobar.
Is there a simple solution?

Many thanks

Gaius