Add horizontal line between rows in a collect environment

[Angira Shukla]

I am trying to run multiple regressions across different specifications and I need to export the results where the dependent variables are rows instead of columns and independent variables in subgroups are columns. I am using Stata's collect commands to create this customized table.

For example:

sysuse auto.dta 
collect drop _all
collect create price
quietly: collect: reg price mpg rep78 
quietly: collect: reg price mpg rep78 

collect create trunk
quietly: collect: reg trunk mpg rep78 if foreign==1
quietly: collect: reg trunk mpg rep78 if foreign==1

collect combine new= price trunk
collect layout  (coleq#result[_r_b _r_se]) (cmdset#colname[mpg rep78] extra)


collect stars _r_p 0.01 "***" 0.05 "** " 0.1 "* ", attach(_r_b) shownote

collect style row stack, spacer delimiter(" x ")

collect label levels cmdset 1 "Pooled" 2 "Foreign", modify

collect style cell cell_type[item column-header], halign(center)
collect style cell, nformat(%5.3f)
collect style cell border_block, border(right, pattern(nil))
collect style cell result[_r_se], sformat("(%s)")
collect style header result, level(hide)
collect style column, dups(center)

collect preview

gives me the following result:

---------------------------------------------------------------------------------------
                                   Pooled                           Foreign            
                      Mileage (mpg) Repair record 1978 Mileage (mpg) Repair record 1978
---------------------------------------------------------------------------------------
Price                  -271.643***       666.957*       -271.643***       666.957*     
                         (57.771)        (342.356)        (57.771)        (342.356)    
                                                                                       
Trunk space (cu. ft.)     -0.098           0.368           -0.098           0.368      
                         (0.121)          (1.061)         (0.121)          (1.061)     
---------------------------------------------------------------------------------------
*** p<.01, ** p<.05, * p<.1

I want to add a horizontal line between the price model and trunk space model but adding the following code adds a new empty row that I don't need.

 
collect style cell coleq[trunk], border(top, pattern(single))

---------------------------------------------------------------------------------------
                                   Pooled                           Foreign            
                      Mileage (mpg) Repair record 1978 Mileage (mpg) Repair record 1978
---------------------------------------------------------------------------------------
Price                  -271.643***       666.957*       -271.643***       666.957*     
                         (57.771)        (342.356)        (57.771)        (342.356)    
---------------------------------------------------------------------------------------
                                                                                       
---------------------------------------------------------------------------------------
Trunk space (cu. ft.)     -0.098           0.368           -0.098           0.368      
---------------------------------------------------------------------------------------
                         (0.121)          (1.061)         (0.121)          (1.061)     
---------------------------------------------------------------------------------------
*** p<.01, ** p<.05, * p<.1

Is there a cleaner way to get a horizontal line and some additional text as a row header?